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

Example Input: Problem: the sum of the even numbers between 1 and n is 89 * 90 , where n is an odd number , then n = ?
Example Output: 179

Example Input: Problem: a hiker walking at a constant rate of 4 kilometers per hour is passed by a cyclist travelling in the same direction along the same path at a constant rate of 24 kilometers per hour . the cyclist stops and waits for the hiker 5 minutes after passing her while the hiker continues to walk at her constant rate . how many minutes must the cyclist wait until the hiker catches up ?
Example Output: 25

Example Input: Problem: there are 4 people of different heights standing in order of increasing height . the difference is 2 inches between the first person and the second person , and also between the second person and the third person . the difference between the third person and the fourth person is 6 inches and the average height is 78 . how tall is the fourth person ?
Example Output:
84