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

Example Input: Problem: a dealer purchases 15 articles for rs . 25 and sells 12 articles for rs . 32 . find the profit percentage ?
Example Output: 60 

Example Input: Problem: if 1 / ( x + 4 ) + 1 / ( x - 4 ) = 1 / ( x - 4 ) , what is the value of x ?
Example Output: 4

Example Input: Problem: in 1950 , richard was 4 times as old as robert . in 1955 , richard was 3 times as old as robert . in which year was richard 1.5 times as old as robert ?
Example Output:
200