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

Ex Input:
Problem: if a a b = 2 a - 3 b + ab , then 3 a 2 + 2 a 3 is equal to :

Ex Output:
7

Ex Input:
Problem: the average score of a cricketer in 2 matches is 60 and in other 3 matches is 50 . then find the average score in all the 5 matches ?

Ex Output:
54

Ex Input:
Problem: what is the rate percent when the simple interest on rs . 800 amount to rs . 160 in 5 years ?

Ex Output:
4