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

Ex Input:
Problem: a cycle is bought for rs . 900 and sold for rs . 1080 , find the gain percent ?

Ex Output:
20 %

Ex Input:
Problem: if shares of two persons in profits are rs . 600 and rs . 1000 then ratio of their capitals is

Ex Output:
3 : 5

Ex Input:
Problem: if 3 a 3 b 2 c = 32 and 3 a - ( 2 b + 2 c ) = 4 , what is the value of a + b + c ?

Ex Output:
10