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

Ex Input:
Problem: a swimmer can swim in still water at 4 km / h . if the speed of the water current is 2 km / h , how many hours will the swimmer take to swim against the current for 5 km ?

Ex Output:
2.5


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: p and q invested in a shop . the profits were divided in the ratio of 4 : 6 respectively . if p invested rs . 55,000 , the amount invested by q is :

Ex Output:

non