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

Example Input: Problem: a is twice as good a workman as b and they took 6 days together to do the work b alone can do it in .
Example Output: 18 days

Example Input: Problem: for any positive integer n , the sum of the first n positive integers equals n ( n + 1 ) / 2 . what is the sum of odd all the integers between 10 and 100 ?
Example Output: 2475

Example Input: Problem: 3 pumps , working 8 hours a day , can empty a tank in 2 days . how many hours a day must 15 pumps work to empty the tank in 1 day ?
Example Output:
3.5