The task is to generate the correct answer for a given math problem.

Ex Input:
Problem: in a class of 32 students , 2 students did not borrow any books from the library , 12 students each borrowed 1 book , 10 students each borrowed 2 books , and the rest borrowed at least 3 books . if the average number of books per student was 2 , what is the maximum number of books any single student could have borrowed ?

Ex Output:
11

Ex Input:
Problem: the curved surface of a sphere is 64 cm 2 . find its radius ?

Ex Output:
4', 'd ) 9', 'e ) 7'

Ex Input:
Problem: by selling 20 pencils for a rupee a man loses 30 % . how many for a rupee should he sell in order to gain 30 % ?

Ex Output:
10.75