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

Example Input: Problem: a train running at the speed of 70 km / hr crosses a pole in 9 sec . what is the length of the train ?
Example Output: 175 m

Example Input: Problem: a person want to give his money of $ 1800 to his 3 children a , b , c in the ratio 2 : 3 : 4 . what is the b ' s share ?
Example Output: $ 600

Example Input: Problem: if x / 2 = y / 5 = z / 6 , then ( x + y + z ) / x is equal to :
Example Output:
13 / 2