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

Ex 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 ?

Ex Output:
60 


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

Ex Output:
5 : 3'


Ex Input:
Problem: edward earns $ 7.00 per hour for the first 40 hours he works per week , and twice this rate for overtime . if michael earned $ 210 last week , how many hours did he work ?

Ex Output:

45