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

Ex Input:
Problem: . 005 / ? = . 01

Ex Output:
. 5

Ex Input:
Problem: the ratio between the sale price and the cost price of an article is 12 : 7 . what is the ratio between the profit and the cost price of that article ?

Ex Output:
5 : 7

Ex Input:
Problem: the average age of a , b and c is 26 years . if the average age of a and c is 29 years , what is the age of b in years ?

Ex Output:
20