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

Ex Input:
Problem: jack and jill are marathon runners . jack can finish a marathon ( 42 km ) in 7 hours and jill can run a marathon in 4.2 hours . what is the ratio of their average running speed ? ( jack : jill )

Ex Output:
5 / 5


Ex Input:
Problem: h is a positive integer and 225 and 216 are both divisors of h . if h = ( 2 ^ a ) * ( 3 ^ b ) * ( 5 ^ c ) , where a , b and c are positive integers , what is the least possible value of a + b + c ?

Ex Output:
8


Ex Input:
Problem: a car salesman earns a base salary of $ 1000 per month plus a commission of $ 200 for each car he sells . if the car salesman earned $ 2000 in march , how many cars does he need to sell in april in order to double his march earnings ?

Ex Output:

15