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

Input: Consider Input: Problem: by selling an article for $ 225 a person gains $ 75 . what is the gain % ?

Output: 50 %

Input: Consider Input: Problem: if p represents the product of the first 16 positive integers , then p is not a multiple of

Output: 5

Input: Consider Input: Problem: if 6 is one solution of the equation x ^ 2 + 3 x + k = 10 , where k is a constant , what is the other solution ?
Output: - 9