TASK DEFINITION: The task is to generate the correct answer for a given math problem.
PROBLEM: Problem: if the cost price of 50 articles is equal to the selling price of 40 articles , then the gain or loss percent is ?

SOLUTION: 25 %

PROBLEM: Problem: if each side of a square is increased by 325 % in length , find the percentage change in its area ?

SOLUTION: 956.25 %

PROBLEM: Problem: what is the sum of all the multiples of 10 between 0 and 99 ?

SOLUTION:
450