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Question: in 10 years , a will be twice as old as b was 10 years ago . if a is now 9 years older than b the present age of b is A.37. B.38. C.39. D.40. e ) 41C. "let present age of a be a and b be b a + 10 = 2 * ( b - 10 ) = > 2 b - a = 30 . . . . . . ( i ) a = b + 9 = > 2 b - b - 9 = 30 b = 39 so the present age of b is 39 years answer : c"
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Question: a reduction of 15 % in the price of salt enables a lady to obtain 10 kgs more for rs . 100 , find the original price per kg ? A.2.8. B.2.3. C.1.8. D.2.1. e ) 2.9C. "100 * ( 15 / 100 ) = 15 - - - 10 ? - - - 1 = > rs . 1.5 100 - - - 85 ? - - - 1.5 = > rs . 1.8 answer : c"
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Question: on the first of the year , james invested x dollars at proudstar bank in an account that yields 2.5 % in interest every quarter year . at the end of the year , during which he made no additional deposits or withdrawals , he had y dollars in the account . if james had invested the same amount in an account which pays interest on a yearly basis , what must the interest rate be for james to have y dollars at the end of the year ? A.22.04 %. B.16.12 %. C.8 %. D.18.25 %. e ) 10.5 %E. per quarter , interest = 2.5 % so for a year , interest = 10 % due to quarter cumulation , effective yield ( ytm ) would be slight higher than 10 % answer = 10.5 % = answer : e
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Question: a train which has 250 m long , is running 40 kmph . in what time will it cross a person moving at 4 kmph in same direction ? A.30 sec. B.28 sec. C.29 sec. D.35 sec. e ) 25 secE. "time taken to cross a moving person = length of train / relative speed time taken = 250 / ( ( 40 - 4 ) ( 5 / 18 ) = 250 / 36 * ( 5 / 18 ) = 250 / 10 = 25 sec answer : e"
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Question: two tains of equal lengths take 10 seconds and 15 seconds respectively to cross a telegraph post . if the length of each train be 120 metres , in what time ( in seconds ) will they cross each other travelling in opposite direction ? A.12. B.14. C.16. D.20. e ) 18A. "sol . speed of the first train = [ 120 / 10 ] m / sec = 12 m / sec . speed of the second train = [ 120 / 15 ] m / sec = 8 m / sec . relative speed = ( 12 + 8 ) = m / sec = 20 m / sec . ∴ required time = ( 120 + 120 ) / 20 secc = 12 sec . answer a"
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Question: if x is a positive number and 2 the square root of x is equal to x / 2 , then x = A.1 / 16. B.4. C.1. D.2. e ) 8C. "2 of sqrt ( x ) = x / 2 , which means that sqrt ( x ) = x or x = x ^ 2 - > divide by x 1 = x x = 1 c ."
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Question: two trains of length 100 m and 200 m are 100.00001 m apart . they start moving towards each other on parallel tracks , at speeds 108 kmph and 72 kmph . in how much time will the trains cross each other ? A.8. B.7. C.9. D.2. e ) 1A. "relative speed = ( 108 + 72 ) * 5 / 18 = 50 mps . the time required = d / s = ( 100 + 100 + 200 ) / 50 = 400 / 50 = 8 sec . answer : a"
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Question: in what ratio mental a at rs . 68 per kg be mixed with another metal at rs . 96 per kg so that cost of alloy ( mixture ) is rs . 82 per kg ? A.5 : 8. B.4 : 7. C.3 : 7. D.1 : 1. e ) 9 : 8D. "( 96 - 82 ) / ( 82 - 68 ) = 14 / 14 = 1 / 1 answer : d"
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Question: if a ( a + 2 ) = 48 and b ( b + 2 ) = 48 , where a ≠ b , then a + b = A.- 10. B.- 9. C.- 5. D.- 4. e ) - 2B. "i . e . if a = 6 then b = - 8 or if a = - 8 then b = 6 but in each case a + b = - 8 + 6 = - 2 answer : b"
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Question: an article with cost price of 240 is sold at 20 % profit . what is the selling price ? A.288. B.200. C.204. D.207. e ) 210A. "sp = 1.20 * 240 = 288 answer : a"
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Question: how many seconds will it take for a car that is traveling at a constant rate of 120 miles per hour to travel a distance of 77 yards ? ( 1 mile = 1,160 yards ) A.1.25. B.1.31. C.1.58. D.1.87. e ) 2.3B. "speed = 120 miles / hr = 58.67 yard / s distance = 77 yards time = distance / speed = 77 / 58.67 = 1.31 sec ans - b"
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Question: a box contains 100 balls , numbered from 1 to 100 . if 3 balls are selected at random and with replacement from the box . if the 3 numbers on the balls selected contain two odd and one even . what is the probability r that the first ball picked up is odd numbered ? A.0. B.1 / 3. C.1 / 2. D.2 / 3. e ) 1D. "answer - d selecting the balls either even or odd is having probability 50 / 100 = 1 / 2 we have already selected 3 balls with 2 odd numbers and 1 even number . so we have 3 combinations ooe , oeo , eoo . we have 3 outcomes and 2 are favourable as in 2 cases 1 st number is odd . so probability r is 2 / 3 . d"
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Question: a store reported total sales of $ 460 million for february of this year . if the total sales for the same month last year was $ 320 million , approximately what was the percent increase in sales ? A.2 %. B.17 %. C.44 %. D.65 %. e ) 83 %C. "new value – old value ) / old value x 100 we are given : february sales this year = 460 million february sales last year = 320 million we need to determine the percent increase between sales from last year to sales this year . thus , the new value = 460 million and the old value = 320 million . let ’ s plug them into our percent change formula . ( new value – old value ) / old value x 100 [ ( 460 – 320 ) / 320 ] x 100 ≈ 44 % . the answer is c ."
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Question: water boils at 212 ° f or 100 ° c and ice melts at 32 ° f or 0 ° c . if the temperature of a pot of water is 55 ° c , what is the temperature of the pot of water in ° f ? A.116 ° f. B.125 ° f. C.131 ° f. D.138 ° f. e ) 145 ° fC. "let f and c denote the temperature in fahrenheit and celsius respectively . ( f - 32 ) / ( 212 - 32 ) = ( c - 0 ) / ( 100 - 0 ) f = 9 c / 5 + 32 f = 9 ( 55 ) / 5 + 32 = 131 ° f the answer is c ."
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Question: what distance will be covered by a bus moving at 126 kmph in 10 seconds ? A.287. B.600. C.350. D.276. e ) 207C. "126 kmph = 126 * 5 / 18 = 35 mps d = speed * time = 35 * 10 = 350 m . answer : c"
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Question: the dimensions of a room are 10 m x 7 m x 5 m . there are 2 doors and 3 windows in the room . the dimensions of the doors are 1 m x 3 m . one window is of size 2 m x 1.5 m and the other 2 windows are of size 1 m x 1.5 m . the cost of painting the walls at rs . 3 per sq m is A.2488. B.378. C.739. D.474. e ) 291D. explanation : area of 4 walls = 2 ( l + b ) h = 2 ( 10 + 7 ) x 5 = 170 sq m area of 2 doors and 3 windows = 2 ( 1 x 3 ) + ( 2 x 1.5 ) + 2 ( 1 x 1.5 ) = 12 sq m area to be planted = 170 - 12 = 158 sq m cost of painting = rs . 158 x 3 = rs . 474 answer : d
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Question: o ( x ) represents the least odd integer greater than x , whereas o ( x ) represents the greatest odd integer less than x . likewise , e ( x ) represents the least even integer greater than x , whereas e ( x ) represents the greatest even integer less than x . according to these definitions , the value of o ( 5.3 ) + e ( – 6.7 ) + o ( – 7.3 ) + e ( 6.6 ) is : A.- 4. B.- 2. C.0. D.2. e ) 4B. o ( 5.3 ) + e ( – 6.7 ) + o ( – 7.3 ) + e ( 6.6 ) = 7 + ( - 6 ) + ( - 9 ) + 6 = - 2 the answer is b .
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Question: a quadratic function f ( x ) attains a maximum of 3 at x = 1 . the value of the function at x = 0 is 1 . what is the value of f ( x ) at x = 10 ? A.- 119. B.- 159. C.- 110. D.- 180. e ) - 105B. explanation : let , the quadratic equation be ax 2 + bx + c . so , f ( x ) = ax 2 + bx + c at x = 0 , the value of function is 1 . x = 0 , f ( x ) = 1 ax 2 + bx + c = a * 0 + b * 0 + c = c c = 1 . at x = 1 , f ( x ) = 3 x = 1 , f ( x ) = 3 a * 1 + b * 1 + c = 3 since c = 1 , a + b = 2 . also , we know that f ( x ) is maximum when x = 1 . if f ( x ) is maximum , ( dx / dt ) ( f ( x ) ) = 0 differentiating f ( x ) , we have d / dt ( ax 2 + bx + c ) = 2 ax + b at x = 1 , 2 ax + b = 0 . 2 a + b = 0 . b = - 2 a . substituting we have a + b = 2 , or a + - 2 a = 2 . a = - 2 . so , b = 4 . so the equation is - 2 x 2 + 4 x + 1 . at x = 10 , the value is - 2 * 100 + 4 * 10 + 1 i . e - 159 . answer : b
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Question: in a certain company , a third of the workers do not have a retirement plan . 40 % of the workers who do not have a retirement plan are women , and 40 % of the workers who do have a retirement plan are men . if 120 of the workers of that company are men , how many of the workers are women ? A.80. B.95. C.105. D.120. e ) 137E. "set up equation : x = total number of workers 120 = 0,4 * 2 / 3 * x + 0,6 * 1 / 3 * x 120 = 14 / 30 x x = 257 257 - 120 = 137 answer e"
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Question: the credit card and a global payment processing companies have been suffering losses for some time now . a well known company recently announced its quarterly results . according to the results , the revenue fell to $ 48.0 billion from $ 72.0 billion , a year ago . by what percent did the revenue fall ? A.20.8. B.30.4. C.31.8. D.32.5. e ) 33.3E. "$ 72 - $ 48 = 24 $ ( 24 / 72 ) * 100 = 33.33 % answer : e"
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Question: a trader bought a car at 10 % discount on its original price . he sold it at a 80 % increase on the price he bought it . what percent of profit did he make on the original price ? A.17 %. B.62 %. C.12 %. D.19 %. e ) 22 %B. "original price = 100 cp = 90 s = 90 * ( 180 / 100 ) = 162 100 - 162 = 62 % answer : b"
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Question: sue ' s trail mix is 30 % nuts and 70 % dried fruit . jane ' s trail mix is 60 % nuts and 40 % chocolate chips . if the combined mixture of sue and jane ' s trails mix contains 40 % nuts , what percent of the combined mixture is dried fruit ? A.16.7 %. B.23.33 %. C.25 %. D.33.3 %. e ) 46.7 %E. "40 % is 10 % - points above 30 % and 20 % - points below 60 % . so the ratio of sue ' s mix to jane ' s mix is 2 : 1 . 2 / 3 * 70 % = 140 % / 3 = 46.7 % the answer is e ."
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Question: a man buys a cycle for rs . 2800 and sells it at a loss of 25 % . what is the selling price of the cycle ? A.s . 2090. B.s . 2160. C.s . 2100. D.s . 2202. e ) s . 2092C. "s . p . = 75 % of rs . 2800 = rs . 75 x 2800 / 100 = rs . 1190 answer : option c"
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Question: if 42.12 = k ( 14 + m / 50 ) , where k and m are positive integers and m < 50 , then what is the value of k + m ? A.5. B.7. C.8. D.9. e ) 10A. "42.12 = 14 k + km / 50 . . . we can rewrite the number as follows : 42 + 0.12 = 14 k + km / 50 . . . . . . . . since k is integer , then 42 = 14 k . . . . . . . . . . k = 3 0.12 = km / 50 . . . . . . 12 / 100 = 3 m / 50 . . . . . . m = 2 k + m = 3 + 2 = 5 answer : a"
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Question: the ratio of a to b is 4 to 5 , where a and b are positive . if x equals a increased by 25 percent of a , and m equals b decreased by 40 percent of b , what is the value of m / x ? A.2 / 5. B.3 / 4. C.4 / 5. D.5 / 4. e ) 3 / 5E. a / b = 4 / 5 m / x = ( 3 / 5 ) * 5 / ( 5 / 4 ) * 4 = 3 / 5 the answer is e .
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Question: a , b and c rents a pasture for rs . 730 . a put in 12 horses for 8 months , b 16 horses for 9 months and 18 horses for 6 months . how much should c pay ? A.270. B.199. C.676. D.156. e ) 227E. "12 * 8 : 16 * 9 = 18 * 6 8 : 12 : 9 9 / 29 * 730 = 227 answer : e"
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Question: the area of a triangle is with base 10 m and height 5 m ? A.11. B.25. C.787. D.122. e ) 12B. "1 / 2 * 10 * 5 = 25 m 2 answer : b"
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Question: a certain fraction is equivalent to 2 / 5 . if the numerator of the fraction is increased by 4 and the denominator is doubled , the new fraction is equivalent to 1 / 4 . what is the sum of the numerator and denominator of the original fraction ? A.49. B.35. C.56. D.26. e ) 21C. "x / y = 2 / 5 - > 1 ( x + 4 ) / 2 y = 1 / 4 - > 2 divide 1 by 2 : = > 2 x / ( x + 4 ) = 8 / 5 = > 5 x = 4 x + 16 = > x = 16 = > y = 5 / 2 * 16 = 40 so x + y = 56 the answer is c"
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Question: how many diagonals does a polygon with 13 sides have , if one of its vertices does not connect to any diagonal ? A.65. B.62. C.58. D.54. e ) 60D. "if i calculate it using the formulae , # diagonals = n ( n - 3 ) / 2 each vertex sends of n - 3 diagonals n = 13 - 1 then 12 * ( 12 - 3 ) / 2 = 54 correct option : d"
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Question: a car averages 30 miles per hour for the first 5 hours of a trip and averages 42 miles per hour for each additional hour of travel time . if the average speed for the entire trip is 38 miles per hour , how many hours long is the trip ? A.13. B.14. C.15. D.16. e ) 17C. "let t be the total time of the trip . 30 * 5 + 42 ( t - 5 ) = 38 t 4 t = 210 - 150 t = 15 the answer is c ."
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Question: in a certain country 1 / 5 of 8 = 4 . assuming the same proportion , what would be the value of 1 / 4 of 16 ? A.13. B.12. C.10. D.16. e ) 14C. c 10
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Question: in what ratio must a grocer mix two varieties of pulses costing rs . 15 and rs . 20 per kg respectively so as to get a mixture worth rs . 16.50 per kg ? A.3 : 7. B.5 : 7. C.7 : 3. D.7 : 5. e ) noneC. solution required ratio = 3.50 : 1.50 = 35 : 15 = 7 : 3 . answer c
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Question: a can do a piece of work in 4 days . b can do it in 10 days . with the assistance of c they completed the work in 2 days . find in how many days can c alone do it ? A.22 days. B.20 / 3 days. C.67 days. D.17 / 6 days. e ) 18 daysB. "c = 1 / 2 - 1 / 4 - 1 / 10 = 3 / 20 = > 20 / 3 days answer : b"
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Question: a and b invests rs . 1500 and rs . 4000 respectively in a business . if a doubles his capital after 6 months . in what ratio should a and b divide that year ' s profit ? A.9 : 5. B.9 : 8. C.9 : 2. D.9 : 9. e ) 9 : 16E. "( 1.5 * 6 + 3 * 6 ) : ( 4 * 12 ) 27 : 48 = > 9 : 16 answer : e"
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Question: the length of a rectangular garden is 2 feet longer than 3 times its width . if the perimeter of the garden is 100 feet , find the length of the garden . ['A.42', 'B.38', 'C.28', 'D.57', 'e ) 49']B. let l and w be the length and width of the garden . the statement ` ` the length of a rectangular garden is 2 feet longer than 3 times its width ' ' may be formulated by l = 2 + 3 w the formula for the perimeter is given by p = 2 l + 2 w substitute p and l in the above equation by 100 and 2 + 3 w respectively to obtain 100 = 2 ( 2 + 3 w ) + 2 w solve for w and l w = 12 and l = 2 + 3 w = 38 . check that the perimeter of the rectangular garden is 100 p = 2 l + 2 w = 76 + 24 = 100 correct answer b
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Question: calculate 24 x 99 A.2673. B.2763. C.2637. D.2736. e ) 2376E. "= 24 - 1 = 23 = ( decrement each digit of the number obtained from 9 ) here we got 23 . now = 9 - 2 = 7 and 9 - 3 = 6 . so we have 76 just write these numbers together . that is we have 23 and 76 . hence answer is 2376 answer is e ."
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Question: a fill pipe can fill 1 / 4 of cistern in 16 minutes . in how many minutes , it can fill 3 / 4 of the cistern ? A.24 min. B.30 min. C.48 min. D.26 min. e ) 16 minC. "required time = 16 * 4 * 3 / 4 = 48 minutes answer is c"
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Question: a reduction of 40 % in the price of oil enables a house wife to obtain 8 kgs more for rs . 2400 , what is the reduced price for kg ? A.rs . 120. B.rs . 125. C.rs . 130. D.rs . 135. e ) rs . 140A. "explanation : 2400 * ( 40 / 100 ) = 960 - - - - 8 ? - - - - 1 = > rs . 120 answer : a"
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Question: a trail mix company keeps costs down by employing the peanuts : cashews : almonds ratio of 10 : 4 : 1 in each bag of up to 75 total nuts . what is the maximum percentage by which the company could decrease its number of peanuts per bag and still have peanuts constitute more than half the total amount of nuts ? A.40 %. B.48 %. C.49 %. D.50 %. e ) 58 %B. peanuts = 50 cashews = 20 almonds = 5 we want to remove as many peanuts as possible while still having peanuts represent more than half of the mixture . . . the number of cashews and almonds will stay the same though , so we have 20 + 5 = 25 of those non - peanuts in total . if we had 25 peanuts and 25 non - peanuts , then that would be 50 % exactly . we want more than 50 % though , so we need to add in 1 more peanut . this gives us . . . peanuts = 26 cashews = 20 almonds = 5 the question asked for the decrease in the number of peanuts as a percentage . we started with 50 peanuts and removed 24 = 24 / 50 = 48 % ; answer : b
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Question: there is a 30 % chance that tigers will not win at all during the whole season . there is a 30 % chance that portugeese will not play at all in the whole season . what is the greatest possible probability that the tigers will win and portugeese will play during the season ? A.55 %. B.60 %. C.70 %. D.72 %. e ) 80 %C. "there is a 30 % chance that tigers will not win at all during the whole season we can infer that there is 70 % chance tigers will win . similarly there is a 30 % chance that portugeese will not play at all in the whole season we can also infer that there is 70 % chance that portugeese will play . answer c"
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Question: we bought a total of 90 books at the store . math books cost $ 4 and history books cost $ 5 . the total price was $ 390 . how many math books did we buy ? A.57. B.60. C.63. D.66. e ) 69B. "m + h = 90 h = 90 - m 4 m + 5 h = 390 4 m + 5 * ( 90 - m ) = 390 m = 60 the answer is b ."
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Question: the sum of three consecutive even numbers is 60 . find the middle number of the three ? A.14. B.60. C.18. D.70. e ) 45B. "three consecutive even numbers ( 2 p - 2 ) , 2 p , ( 2 p + 2 ) . ( 2 p - 2 ) + 2 p + ( 2 p + 2 ) = 60 6 p = 60 = > p = 10 . the middle number is : 10 p = 60 . answer : b"
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Question: a number when divided by 133 leaves 16 as a remainder . what will be the remainder if the number is divided by 50 ? A.51. B.56. C.49. D.17. e ) 7C. "133 + 16 = 149 dividing 149 evenly into whole numbers is 2 and leaves 49 remaining . the correct answer is c ."
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Question: the length of a rectangular floor is more than its breadth by 200 % . if rs . 240 is required to paint the floor at the rate of rs . 3 per sq m , then what would be the length of the floor ? A.65. B.44. C.18. D.15.49. e ) 14D. "let the length and the breadth of the floor be l m and b m respectively . l = b + 200 % of b = l + 2 b = 3 b area of the floor = 240 / 3 = 80 sq m l b = 80 i . e . , l * l / 3 = 240 l 2 = 240 = > l = 15.49 answer : d"
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Question: a train 100 m long crosses a platform 125 m long in 15 sec ; find the speed of the train ? A.91.2 kmph. B.61.9 kmph. C.45.9 kmph. D.61.2 kmph. e ) 71.2 kmphD. "d = 100 + 155 = 255 t = 15 s = 255 / 15 * 18 / 5 = 61.2 kmph answer : d"
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Question: john has 10 pairs of matched socks . if he loses 3 individual socks , what is the greatest number of pairs of matched socks he can have left ? A.7. B.8. C.5. D.4. e ) 3B. "because we have to maximize the pair of matched socks , we will remove 1 pairs ( 2 socks ) out of 10 pairs 1 sock from the 2 th pair . thus the no of matching socks pair remaining = 10 - 2 = 8 answer b"
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Question: a train 250 m long is running with a speed of 68 kmph . in what time will it pass a man who is running at 8 kmph in the same direction in which the train is going ? A.6 sec .. B.7 sec .. C.9 sec .. D.15 sec .. e ) noneD. "solution speed of the train relative to man = ( 68 - 8 ) = 60 kmph = 60 x 5 / 18 = 50 / 3 m / sec . time taken by it to cover 250 m at ( 50 / 3 ) m / sec = ( 250 x 3 / 50 ) sec = 15 sec . answer d"
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Question: a garrison of 400 men had a provision for 31 days . after 26 days 275 persons re - enforcement leave the garrison . find the number of days for which the remaining ration will be sufficient ? A.16 days. B.45 days. C.10 days. D.17 days. e ) 18 daysA. "400 - - - 31 400 - - - 5 125 - - - ? 400 * 5 = 125 * x = > x = 16 days . answer : a"
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Question: if the cost price of 50 articles is equal to the selling price of 40 articles , then the gain or loss percent is ? A.33 %. B.29 %. C.25 %. D.55 %. e ) 39 %C. "c 25 % given that , cost price of 50 article is equal to selling price of 40 articles . let cost price of one article = rs . 1 selling price of 40 articles = rs . 50 but cost price of 40 articles = rs . 40 therefore , the trader made profit . \ percentage of profit = 10 / 40 * 100 = 25 %"
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Question: if two dice are thrown together , the probability of getting an even number on both dice is A.1 / 4. B.1 / 5. C.1 / 6. D.1 / 3. e ) 1 / 2A. "the number of exhaustive outcomes is 36 . let e be the event of getting an even number on both dies is 9 / 36 = 1 / 4 p ( e ) = 1 / 4 . a )"
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Question: an alloy of copper and zinc contains copper and zinc in the ratio 8 : 2 . another alloy of copper and zinc contains copper and zinc in the ratio 4 : 6 . in what ratio should the two alloys be mixed so that the resultant alloy contains equal proportions of copper and zinc ? A.5 : 1. B.4 : 1. C.3 : 1. D.6 : 1. e ) 8 : 1C. "let alloy _ 1 be x units , and let alloy _ 2 be y units . so , fraction of copper in alloy _ 1 = 8 x / 10 , and fraction of zinc in alloy _ 1 = 2 x / 10 similarly , fraction of copper in alloy _ 2 = 4 y / 10 , and fraction of zinc in alloy _ 2 = 6 y / 10 . mixing them , we get copper = 8 x / 10 + 4 y / 10 ; zinc = 2 x / 10 + 6 y / 10 so , 8 x + 4 y = 2 x + 6 y - > 6 x = 2 y - > x / y = 6 / 2 = 3 / 1 so , they must be mixed in the ratio 3 : 1 answer : c"
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Question: the average monthly income of p and q is rs . 5050 . the average monthly income of q and r is rs . 6250 and the average monthly income of p and r is rs . 5200 . the monthly income of p + q + r is : A.16100. B.15700. C.17500. D.16000. e ) 16500E. "explanation : let p , q and r represent their respective monthly incomes . then , we have : p + q = ( 5050 x 2 ) = 10100 . . . . ( i ) q + r = ( 6250 x 2 ) = 12500 . . . . ( ii ) p + r = ( 5200 x 2 ) = 10400 . . . . ( iii ) adding ( i ) , ( ii ) and ( iii ) , we get : 2 ( p + q + r ) = 33000 or p + q + r = 16500 . . . . ( iv ) ( p + q + r ) ' s monthly income = rs . 16500 . answer : e"
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Question: if 1 / ( x + 1 ) + 1 / ( x - 1 ) = 1 / ( x - 1 ) , what is the value of x ? A.2. B.- 2. C.1. D.- 1. e ) 5C. if we solve the question , we get x = 1 . option : c
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Question: evaluate 100 ^ 2 - 99 ^ 2 + 98 ^ 2 - 97 ^ 2 + 96 ^ 2 - 95 ^ 2 + . . . + 2 ^ 2 - 1 ^ 2 = ? A.3043. B.5050. C.5176. D.9356. e ) 4890B. b 5050 you must have noticed that 50 pairs of n ^ 2 – ( n - 1 ) ^ 2 exist . n ^ 2 – ( n - 1 ) ^ 2 = n + ( n – 1 ) in such case , we may as well write 100 ^ 2 - 99 ^ 2 + 98 ^ 2 - 97 ^ 2 + 96 ^ 2 - 95 ^ 2 + . . . + 2 ^ 2 - 1 ^ 2 as 100 + 99 + 98 + . . . + 2 + 1 = ( 100 x 101 ) / 2 = 5050
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Question: what percent of 14 is 14 percent of 1 ? A.0.001. B.0.01. C.0.1. D.101. e ) 1E. "14 % of 1 = ( 14 / 100 ) * 1 = 14 / 100 to determine what percentage of 14 this is : [ 14 ] [ / 100 * 14 ] * 100 = 1 % ans : e"
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Question: the annual birth and death rate in a country per 1000 are 39.4 and 19.4 respectively . the number of years r in which the population would be doubled assuming there is no emigration or immigration is A.20. B.r = 25. C.r = 30. D.r = 35. e ) 40D. "suppose the population of the country in current year is 1000 . so annual increase is 1000 + 39.4 - 19.4 = 1020 hence every year there is an increase of 2 % . 2000 = 1000 ( 1 + ( 2 / 100 ) ) ^ n n = 35 answer is d ."
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Question: there are 15 balls in a jar . you take out 3 blue balls without putting them back inside , and now the probability of pulling out a blue ball is 1 / 3 . how many blue balls were there in the beginning ? A.12 .. B.9 .. C.8 .. D.7 .. e ) 6 .D. "7 = 3 blue balls + 12 / 3 answer : d"
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Question: the average ( arithmetic mean ) of 8 numbers is 43.1 . if the sum of half of these numbers is 158.4 , what is the average of the other half ? A.12.8. B.24.2. C.46.6. D.72.1. e ) 96.8C. arithmetic mean = sum / total numbers sum = 43.1 * 8 = 344.8 sum of half of these numbers is 158.4 . so , 4 numbers sum is 158.4 . rest 4 numbers sum = 344.8 - 158.4 = 186.4 arithmetic mean of the 4 nos = 186.4 / 4 = 46.6 hence , c is the answer .
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Question: 12.5 * 6.2 * 8.8 = ? A.352. B.435. C.224. D.682. e ) 742D. "d 682 ? = 12.5 * 6.2 * 8.8 = 682"
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Question: if 5 and 8 are factors of 60 n , what is the minimum value of n ? A.2. B.3. C.7. D.14. e ) 56A. "60 n / 7 * 8 should be integer = > 2 * 2 * 3 * 5 * n / 5 * 2 * 2 * 2 = 3 * n / 2 must be an integer for this to be true n must multiple of 2 , thus min of n = 2 hence a"
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Question: what is the probability of getting exactly 2 heads in a single throw of four fair coins ? A.1 / 2. B.3 / 4. C.3 / 8. D.3 / 16. e ) 5 / 16C. "one possible case is hhtt . p ( hhtt ) = 1 / 2 * 1 / 2 * 1 / 2 * 1 / 2 = 1 / 16 there are 4 c 2 = 6 possible cases . p ( 2 heads ) = 6 * 1 / 16 = 3 / 8 the answer is c ."
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Question: the speed of a car increases by 2 kms after every one hour . if the distance travelling in the first one hour was 45 kms . what was the total distance traveled in 12 hours ? A.252 kms. B.152 kms. C.672 kms. D.752 kms. e ) 152 kmsC. explanation : total distance travelled in 12 hours = ( 45 + 47 + 49 + . . . . . upto 12 terms ) this is an a . p with first term , a = 45 , number of terms , n = 12 , d = 2 . required distance = 12 / 2 [ 2 x 45 + { 12 - 1 ) x 2 ] = 6 ( 112 ) = 672 kms . answer : c
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Question: n denotes the number obtained when n is rounded to the nearest tenth . for example 4.31 = 4.3 0.089 - 1.135 = A.1.05. B.1.04. C.- 1.05. D.- 1.0. e ) - 0.1D. here let the first quantity be a = > a rounded to nearest tenths = > 0.1 similarly let the second quantity be b = > b rounded to nearest tenths = > 1.1 = > a - b = 0.1 - 1.1 = - 1 hence a - b = - 1 answer : d
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Question: if x , y , and z are positive real numbers such that x + y - z = 50 , y - z + x = 60 , and z - x + y = 80 , then find the z value ? A.10. B.20. C.5. D.15. e ) 25C. "x + y - z = 50 , - - - - - - 1 ) y - z + x = 60 , - - - - - - 2 ) z - x + y = 80 - - - - - - 3 ) from ( 1 ) & ( 2 ) 2 z = 10 z = 5 correct option is c"
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Question: initially , the men and women in a room were in the ratio of 4 : 5 . then , 2 men entered the room and 3 women left the room . then , the number of women doubled . now there are 14 men in the room . how many w women are currently in the room ? A.12. B.14. C.15. D.24. e ) 36D. "the number of women doubled means that they have become 24 from 12 . . and we have to tell the current strength so 24 is the answer . . let the number be 4 x and 5 x . . given 4 x + 2 = 14 . . so x = 3 . . women number = 5 * 3 - 3 = 12 , then doubled = 24 . . ans d"
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Question: 12.5 * 3.2 * 7.8 = ? A.312. B.435. C.224. D.646. e ) 742A. "a 312 ? = 12.5 * 3.2 * 7.8 = 312"
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Question: a certain protective additive increases from 30 days to 45 days the time between required maintenance checks on an industrial vehicle . by what percent is the time between maintenance checks increased by using the additive ? A.25 %. B.33 1 / 3 %. C.50 %. D.66 2 / 3 %. e ) 75 %C. general formula for percent increase or decrease , ( percent change ) : percent = change / original ∗ 100 so , the time between maintenance checks increased by 45 − 30 / 30 ∗ 100 = 50 answer : c .
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Question: an optometrist charges $ 150 per pair for soft contact lenses and $ 85 per pair for hard contact lenses . last week she sold 5 more pairs of soft lenses than hard lenses . if her total sales for pairs of contact lenses last week were $ 1,220 , what was the total number of pairs of contact lenses that she sold ? A.9. B.13. C.15. D.17. e ) 19A. "( x + 5 ) * 150 + x * 85 = 1220 = > x = 2 total lens = 2 + ( 2 + 5 ) = 9 answer a"
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Question: a bus trip of 660 miles would have taken 1 hour less if the average speed v for the trip had been greater by 5 miles per hour . what was the average speed v , in miles per hour , for the trip ? A.40. B.45. C.50. D.55. e ) 60D. "the time is the distance / speed . the time difference is 1 hour . 660 / v - 660 / ( v + 5 ) = 1 660 ( v + 5 ) - 660 v = ( v ) ( v + 5 ) 3300 = ( v ) ( v + 5 ) 55 * 60 = ( v ) ( v + 5 ) v = 55 mph the answer is d ."
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Question: a man can row downstream at 35 kmph and upstream at 25 kmph . find the speed of the man in still water and the speed of stream respectively ? A.35. 3. B.25. 5. C.35. 4. D.5. 30. e ) 30. 5E. "let the speed of the man in still water and speed of stream be x kmph and y kmph respectively . given x + y = 35 - - - ( 1 ) and x - y = 25 - - - ( 2 ) from ( 1 ) & ( 2 ) 2 x = 60 = > x = 30 , y = 5 . answer : e"
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Question: in an examination , 300 students appeared . out of these students ; 30 % got first division , 54 % got second division and the remaining just passed . assuming that no student failed ; find the number of students who just passed . A.33. B.37. C.54. D.99. e ) 48E. the number of students with first division = 30 % of 300 = 30 / 100 × 300 = 9000 / 100 = 90 and , the number of students with second division = 54 % of 300 = 54 / 100 × 300 = 16200 / 100 = 162 therefore , the number of students who just passed = 300 – ( 90 + 162 ) = 48 answer : e
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Question: if two dice are thrown together , the probability of getting an even number on one die and an odd number on the other is ? A.1 / 9. B.1 / 2. C.1 / 1. D.1 / 5. e ) 1 / 8B. "the number of exhaustive outcomes is 36 . let e be the event of getting an even number on one die and an odd number on the other . let the event of getting either both even or both odd then = 18 / 36 = 1 / 2 p ( e ) = 1 - 1 / 2 = 1 / 2 . answer : b"
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Question: 5 men are equal to as many women as are equal to 8 boys . all of them earn rs . 45 only . men â € ™ s wages are ? A.6 rs. B.7 rs. C.8 rs. D.4 rs. e ) 3 rsE. "5 m = xw = 8 b 5 m + xw + 8 b - - - - - 45 rs . 5 m + 5 m + 5 m - - - - - 45 rs . 15 m - - - - - - 45 rs . = > 1 m = 3 rs . answer : e"
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Question: one pipe can fill a tank three times as fast as another pipe . if together the two pipes can fill the tank in 34 minutes , then the slower pipe alone will be able to fill the tank in A.144 mins. B.140 mins. C.136 mins. D.132 minw. e ) none of theseC. "explanation : let the slower pipe alone fill the tank in x minutes then faster will fill in x / 3 minutes . part filled by slower pipe in 1 minute = 1 / x part filled by faster pipe in 1 minute = 3 / x part filled by both in 1 minute = 1 / x + 3 / x = 1 / 34 = > 4 / x = 1 / 34 x = 34 ∗ 4 = 136 mins option c"
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Question: two dice are rolled . what is the probability that the sum on the top face of both the dice will be greater than 9 ? A.3 / 8. B.2 / 3. C.1 / 2. D.1 / 3. e ) 1 / 6E. total number of outcomes possible when a die is rolled = 6 ( ∵ any one face out of the 6 faces ) hence , total number of outcomes possible two dice are rolled , n ( s ) = 6 × 6 = 36 e = getting a sum greater than 9 when the two dice are rolled = { ( 4 , 6 ) , { 5 , 5 } , { 5 , 6 } , { 6 , 4 } , { 6 , 5 } , ( 6 , 6 ) } hence , n ( e ) = 6 p ( e ) = n ( e ) / n ( s ) = 6 / 36 = 1 / 6
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Question: let a be the event that a randomly selected two digit number is divisible by 3 and let b be the event that a randomly selected two digit number is divisible by 10 . what is p ( a and b ) ? A.1 / 30. B.1 / 15. C.1 / 5. D.1 / 3. e ) 1 / 2A. "p ( a and b ) = 1 / 3 * 1 / 10 = 1 / 30 the answer is a ."
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Question: if x is 12 percent greater than 80 , then x = A.89.6. B.91.0. C.88.0. D.70.9. e ) 71.2A. "12 % of 80 = ( 80 * 0.12 ) = 9.6 12 % greater than 80 = 80 + 9.6 = 89.6 answer is clearly a ."
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Question: a and b complete a work in 6 days . a alone can do it in 8 days . if both together can do the work in how many days ? A.3.75 days. B.3.43 days. C.2.99 days. D.2.98 days. e ) 2.44 daysB. "1 / 6 + 1 / 8 = 7 / 24 24 / 7 = 3.43 days answer : b"
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Question: the avg weight of a , b & c is 84 kg . if d joins the group , the avg weight of the group becomes 80 kg . if another man e who weights is 8 kg more than d replaces a , then the avgof b , c , d & e becomes 79 kg . what is the weight of a ? A.25. B.35. C.75. D.80. e ) 90D. "a + b + c = 3 * 84 = 252 a + b + c + d = 4 * 80 = 320 - - - - ( i ) so , d = 68 & e = 68 + 8 = 76 b + c + d + e = 79 * 4 = 316 - - - ( ii ) from eq . ( i ) & ( ii ) a - e = 320 â € “ 316 = 4 a = e + 4 = 76 + 4 = 80 d"
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Question: 130 kg of an alloy a is mixed with 160 kg of alloy b . if alloy a has lead and tin in the ratio 2 : 3 and alloy b has tin and copper in the ratio 3 : 4 , then the amount of tin in the new alloy is ? A.140.6 kg. B.145.3 kg. C.146.5 kg. D.110.8 kg. e ) 114 kgC. "quantity of tin in 130 kg of a = 130 * 3 / 5 = 78 kg quantity of tin in 160 kg of b = 160 * 3 / 7 = 68.5 kg quantity of tin in the new alloy = 78 + 68.5 = 146.5 kg answer is c"
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Question: if each side of a square is increased by 325 % in length , find the percentage change in its area ? A.54 %. B.957 %. C.956.25 %. D.958.25 %. e ) 959.50 %C. "let each side of the square be a , then area = a x a new side = 325 a / 100 = 13 a / 4 new area = ( 13 a x 13 a ) / ( 4 x 4 ) = ( 25 a ² / 16 ) increased area = = ( 169 a ² / 16 ) - a ² increase % = [ ( 153 a ² / 16 ) x ( 1 / a ² ) x 100 ] % = 956.25 % answer : c"
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Question: martin bought 10 concert tickets , some at the full price of $ 2.00 per ticket , and some at a discounted price of $ 1.60 per ticket . if he spent a total of $ 18.80 , how many discounted tickets did he buy ? A.3. B.4. C.5. D.6. e ) 7A. "let x be the number of tickets he bought at $ 2 per ticket . then 2 x + ( 10 - x ) 1.6 = 18.8 0.4 x = 2.8 = > x = 7 discounted tickets = 10 - x = 3 ans : a"
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Question: a can do a piece of work in 10 days and b can do it in 15 days and c can do it 20 days . they started the work together and a leaves after 5 days and b leaves after 3 days from the beginning . how long will work lost ? A.2. B.4. C.5. D.6. e ) 7D. "5 / 10 + 3 / 15 + x / 20 = 1 x = 18 / 3 = 6 answer : d"
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Question: at the end of year x , automobile installment credit accounted for 35 % of all outstanding consumer installment credit . at that time automobile finance companies extended $ 40 billion of credit , or 1 / 3 of the automobile installment credit . how many billion dollars of consumer installment credit was outstanding at that time ? A.120. B.300. C.401.36. D.350.15. e ) 342.86E. "system of equations a = ( 35 / 100 ) c ( 1 / 3 ) a = 40 - - > a = 120 substitution 120 = ( 35 / 100 ) c c = ( 100 / 35 ) 120 answer - 120 / 35 * 100 the correct answer is e . - 342.86"
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Question: two numbers are in the ratio 3 : 5 . if 9 be subtracted from each , they are in the ratio of 2 : 3 . the first number is : A.A.27. B.B.98. C.C.34. D.D.35. e ) e ) 62A. "( 3 x - 9 ) : ( 5 x - 9 ) = 2 : 3 x = 9 = > 3 x = 27 answer : a"
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Question: the length of the bridge , which a train 130 metres long and travelling at 54 km / hr can cross in 30 seconds , is : A.200 m. B.225 m. C.320 m. D.250 m. e ) 240 mC. "speed = [ 54 x 5 / 18 ] m / sec = [ 15 / 1 ] m / sec time = 30 sec let the length of bridge be x metres . then , ( 130 + x ) / 30 = 15 = > ( 130 + x ) = 450 = > x = 450 - 130 = 320 m answer : c"
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Question: two kinds of vodka are mixed in the ratio 1 : 2 and 2 : 1 and they are sold fetching the profit 10 % and 40 % respectively . if the vodkas are mixed in equal ratio and the individual profit percent on them are increased by 4 / 3 and 5 / 3 times respectively , then the mixture will fetch the profit of A.18 %. B.20 %. C.21 %. D.40 %. e ) can not be determinedD. answer : d .
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Question: what is 3 2 / 3 - 2 1 / 4 divided by 6 / 7 - 2 / 5 ? A.17 / 36. B.36 / 17. C.17 / 64. D.15 / 4. e ) 14 / 4C. "3 2 / 3 - 2 1 / 4 = 11 / 3 - 9 / 4 = ( 44 - 27 ) / 12 = 17 / 12 6 / 7 - 2 / 5 = ( 30 - 14 ) / 35 = 16 / 35 so 17 / 12 / 16 / 3 = 17 / 12 * 3 / 16 = 17 / 64 answer - c"
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Question: the sum of the ages of 5 children born at the intervals of 3 year each is 50 year . what is the age of the youngest child ? A.4 year. B.8 year. C.10 year. D.none of these. e ) 9 yearA. "solution let the ages of the children be x , ( x + 3 ) , ( x + 6 ) , ( x + 9 ) and ( x + 12 ) year . then , x + ( x + 3 ) + ( x + 6 ) + ( x + 9 ) + ( x + 12 ) = 50 ⇔ 5 x = 20 ⇔ x = 4 . ∴ age of the youngest child = x = 4 years . answer a"
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Question: sara bought both german chocolate and swiss chocolate for some cakes she was baking . the swiss chocolate cost $ 2.5 per pound , and german chocolate cost $ 1.5 per pound . if the total the she spent on chocolate was $ 30 and both types of chocolate were purchased in whole number of pounds , how many total pounds of chocolate she purchased ? A.7. B.18. C.10. D.12. e ) 11B. "if there were all the expensive ones 2.5 . . . . there would be 30 / 2.5 or 12 of them but since 1.5 $ ones are also there , answer has to be > 12 . . . . if all were 1.5 $ ones , there will be 30 / 1.5 or 20 . . . so only 18 is left ans b . ."
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Question: the total age of a and b is 16 years more than the total age of b and c . c is how many year younger than A.14 years. B.12 years. C.56 years. D.16 years. e ) 55 yearsD. "given that a + b = 16 + b + c = > a â € “ c = 16 + b â € “ b = 16 = > c is younger than a by 16 years answer : d"
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Question: the area of sector of a circle whose radius is 12 metro and whose angle at the center is 30 ° is ? ['A.35 m 2', 'B.36 m 2', 'C.37 m 2', 'D.38 m 2', 'e ) 40 m 2']C. 30 / 360 * 22 / 7 * 12 * 12 = 37 m 2 answer : c
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Question: find large number from below question the difference of two numbers is 1360 . on dividing the larger number by the smaller , we get 6 as quotient and the 15 as remainder A.1254. B.1376. C.1456. D.1555. e ) 1629E. "let the smaller number be x . then larger number = ( x + 1360 ) . x + 1360 = 6 x + 15 5 x = 1345 x = 269 large number = 269 + 1360 = 1629 e"
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Question: solve the equation 2 – x = 2 b – 2 ax , where a and b are real parameters . find for which values of a the equation has for solution a natural number , if b = 7 A.0. B.1. C.2. D.3. e ) 4B. solution : we write the given equation like this ( 2 a - 1 ) x = 2 ( b - 1 ) the following cases are possible : if 2 a - 1 ≠ 0 , i . e . a ≠ 1 / 2 , the equation has single solution x = 2 ( b - 1 ) / ( 2 a - 1 ) if a = 1 / 2 and b = 1 , the equation gets the kind 0 . x = 0 and every x is solution if a = 1 / 2 and b ≠ 1 , we get 0 . x = 2 ( b - 1 ) , where 2 ( b - 1 ) ≠ 0 in this case the equation has no solution . if b = 7 and a ≠ 1 / 2 the single solution is x = 2 ( 7 - 1 ) / ( 2 a - 1 ) = 12 / ( 2 a - 1 ) if a is whole number , then 2 a - 1 is also whole number and the solution x = 12 / ( 2 a - 1 ) is natural number when 2 a - 1 is positive divisor of 12 . to have a as whole number , the divisor of 12 mu be odd . but the only whole positive odd numbers divisible by 12 are 1 and 3 . therefore 2 a - 1 = 3 < = > a = 2 or 2 a - 1 = 1 < = > a = 1 a = 2 or 2 a - 1 = 1 < = > a = 1 answer b
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Question: in a caravan , in addition to 50 hens there are 45 goats and 8 camels with some keepers . if the total number of feet be 224 more than the number of heads , find the number of keepers . A.25. B.20. C.15. D.13. e ) 14C. let the number of keepers be x then , total number of heads = ( 50 + 45 + 8 + x ) = ( 103 + x ) . total number of feet = ( 45 + 8 ) x 4 + ( 50 + x ) x 2 = ( 312 + 2 x ) . ( 312 + 2 x ) - ( 103 + x ) = 224 = = > x = 15 . hence , number of keepers = 15 . answer c .
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Question: a motorcyclist goes from bombay to pune , a distance of 160 kms at an average of 32 kmph speed . another man starts from bombay by car 2 ½ hours after the first , and reaches pune ½ hour earlier . what is the ratio of the speed of the motorcycle and the car ? A.1 : 2. B.2 : 5. C.1 : 4. D.1 : 1. e ) 1 : 6B. "t = 160 / 32 = 5 h t = 5 - 3 = 2 time ratio = 5 : 2 = 5 : 2 speed ratio = 2 : 5 answer : b"
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Question: what will be the percentage increase in the area of the cube ' s surface if each of the cube ' s edges grows by 40 % ? A.95 %. B.90 %. C.85 %. D.96 %. e ) 25 %D. "the question is very easy . my logic is the following : a surface = 6 * a ^ 2 after 40 % increase a surface = 6 * ( ( 1.4 a ) ^ 2 ) = 6 * 1.96 * a ^ 2 the increase in the surface area = ( 6 * 1.96 * a ^ 2 - 6 * a ^ 2 ) / 6 * a ^ 2 = ( 6 * a ^ 2 ( 1.96 - 1 ) ) / ( 6 * a ^ 2 ) = 1.96 - 1 = 0.96 = 96 % answer : d"
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Question: how many shots of 1 cm radius can be prepared from a sphere of 5 cm radius ? A.33. B.88. C.27. D.125. e ) 199D. 4 / 3 ï € * 5 * 5 * 5 = 4 / 3 ï € * 1 * 1 * 1 * x x = 125 answer : d
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Question: in a village there are 150 men and 90 women in present time . if in next year population will be p = ( a ^ 2 + b ^ 2 ) ^ 1 / 2 , and in every year men are reduces 10 % . what is population of after 2 year . A.140. B.141. C.142. D.143. e ) 144B. next year total population = [ 150 ^ 2 + 90 ^ 2 ] ^ . 5 = 174.92 = 175 man decreased by 10 % so total man = 150 * . 9 = 135 women will be = 175 - 135 = 40 so population after two years = [ 135 ^ 2 + 40 ^ 2 ] ^ . 5 = 140.80 = 141 so population after two year = 141 answer : b
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Question: a train 124 m long running at 68 kmph crosses a platform in 19 sec . what is the length of the platform ? A.338. B.234. C.240. D.881. e ) 271B. "d = 68 * 5 / 18 = 19 = 358 – 124 = 234 answer : b"
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