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

Example Input: Problem: two trains travel in opposite directions at 36 kmph and 45 kmph and a man sitting in slower train passes the faster train in 12 seconds . the length of the faster train is
Example Output: 270 m

Example Input: Problem: 5 men are equal to as many women as are equal to 8 boys . all of them earn $ 90 only . men ' s wages are ?
Example Output: $ 6

Example Input: Problem: a person can swim in still water at 12 km / h . if the speed of water 10 km / h , how many hours will the man take to swim back against the current for 8 km ?
Example Output:
4