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

Ex Input:
Problem: if a drawing has an outer circle of diameter 30 and an inner circle of diameter 24 , then what fraction of outer circle ' s surface is not covered by the inner circle ?

Ex Output:
9 / 25', 'e ) 2 / 3'


Ex Input:
Problem: the average of first 10 odd numbers is ?

Ex Output:
10


Ex Input:
Problem: a , b and c invested rs . 6300 , rs . 4200 and rs . 10500 respectively , in a partnership business . find the share of a in profit of rs . 12500 after a year ?

Ex Output:

3750