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

Example Input: Problem: at what rate percent on simple interest will rs . 750 amount to rs . 900 in 8 years ?
Example Output: 2.5 %

Example Input: Problem: a man , a woman and a boy can together complete a piece of work in 3 days . if a woman alone can do it in 6 days and a boy alone in 18 days , how long will a man take to complete the work ?
Example Output: 9 days

Example Input: Problem: the cost price of 40 articles is the same as the selling price of x articles . if the profit is 25 % , what is x ?
Example Output:
32