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

Input: Consider Input: Problem: by selling an article for $ 195 , a person gains $ 45 . what is the gain % ?

Output: 30 %

Input: Consider Input: Problem: what is the sum of natural numbers between 30 and 100

Output: 4615

Input: Consider Input: Problem: if the personal income tax rate is lowered from 46 % to 32 % , what is the differential savings for a tax payer having an annual income before tax to the tune of $ 36000 ?
Output: $ 5040