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

Example Input: Problem: a train passes a station platform in 30 sec and a man standing on the platform in 20 sec . if the speed of the train is 54 km / hr . what is the length of the platform ?
Example Output: 60 

Example Input: Problem: if the sides of a cube are in the ratio 5 : 3 . what is the ratio of their diagonals ?
Example Output: 5 : 3'

Example Input: Problem: what is 82 % of 3 / 5 ?
Example Output:
0.492