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

Example Input: Problem: two cars start at the same time from opposite ends of a highway that is 175 miles long . one car is riding at 25 mph and the second car is riding at 45 mph . how long after they begin will they meet ?
Example Output: 2.5

Example Input: Problem: for any integer n greater than 1 , n * denotes the product of all the integers from 1 to n , inclusive . how many prime numbers are there between 6 * + 2 and 6 * + 6 , inclusive ?
Example Output: none

Example Input: Problem: a train 250 m long passed a pole in 10 sec . how long will it take to pass a platform 1250 m long ?
Example Output:
60 sec