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

Example Input: Problem: two trains running in opposite directions cross a man standing on the platform in 37 seconds and 27 seconds respectively and they cross each other in 29 seconds . the ratio of their speeds is :
Example Output: 1 : 

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 case contains c cartons . each carton contains b boxes , and each box contains 600 paper clips . how many paper clips are contained in 2 cases ?
Example Output:
1200 bc