Problem: one side of a rectangle is 3 cm shorter than the other side . if we increase the length of each side by 1 cm , then the area of the rectangle will increase by 20 cm 2 . find the lengths of all sides . 
Options: a ) 10 and 3 , b ) 7 and 10 , c ) 11 and 8 , d ) 3 and 10 , e ) 10 and 10
c