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

Example Input: Problem: a man can do a piece of work in 7 days , but with the help of his son , he can finish it in 3 days . in what time can the son do it alone ?
Example Output: 4 1 / 5

Example Input: Problem: a = 5 ^ 10 - 625 ^ 2 and a / x is an integer , where x is a positive integer greater than 1 , such that it does not have a factor p such that 1 < p < x , then how many different values for x are possible ?
Example Output: two

Example Input: Problem: crazy eddie has a key chain factory . eddie managed to decrease the cost of manufacturing his key chains while keeping the same selling price , and thus increased the profit from the sale of each key chain from 20 % of the selling price to 50 % of the selling price . if the manufacturing cost is now $ 50 , what was it before the decrease ?
Example Output:
$ 80