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

Ex Input:
Problem: when the price of a product was decreased by 20 % , the number sold increased by 60 % . what was the effect on the total revenue ?

Ex Output:
28 %


Ex Input:
Problem: a van takes 5 hours to cover a distance of 495 km . what speed in kph should the van maintain to cover the same distance in 3 / 2 of the previous time ?

Ex Output:
66


Ex Input:
Problem: if 10 men can reap 80 hectares in 24 days , then how many hectares can 36 men reap in 30 days ?

Ex Output:

360