Previous year results report that 30% of all
students who reside in hostel attain A grade and 20% of day scholars attain A
grade in their annual examination At the end of the year, one student is chosen
at random from the college and he has an A grade, what is the probability that the
student is a hostlier 4 In answering a question on a multiple choice test, a student either knows the
answer or guesses