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

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: find the area of trapezium whose parallel sides are 20 cm and 18 cm long , and the distance between them is 10 cm ?

Ex Output:
190 cm 


Ex Input:
Problem: a can do a half of certain work in 70 days and b one third of the same in 35 days . they together will do the whole work in ?

Ex Output:

1 / 60