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

Example Input: Problem: carl is facing very difficult financial times and can only pay the interest on a $ 10,000 loan he has taken . the bank charges him a quarterly compound rate of 8 % . what is the approximate interest he pays annually ?
Example Output: 3500

Example Input: Problem: the number of positive integer solutions for the equation x + y + z + t = 30 is
Example Output: 3654

Example Input: Problem: if a sum of money doubles itself in 25 years at simple interest , the ratepercent per annum is
Example Output: