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

Ex Input:
Problem: find compound interest on $ 10000 at 15 % per annum for 2 years 4 months , compounded annually .

Ex Output:
3886.25

Ex Input:
Problem: income and expenditure of a person are in the ratio 7 : 6 . if the income of the person is rs . 14000 , then find his savings ?

Ex Output:
2000

Ex Input:
Problem: a train of 30 carriages , each of 60 meters length , when an engine also of 60 meters length is running at a speed of 60 kmph . in what time will the train cross a bridge 1.5 km long ?

Ex Output:
3.3