The task is to generate the correct answer for a given math problem.
--------
Question: Problem: the length of a rectangle is increased by 15 % and its breadth is decreased by 20 % . what is the effect on its area ?

Answer: 920


Question: Problem: the distance between a & b is 1540 km . a person is traveling from a to b at 100 km / hr started at 6 am and another person is traveling from b to a at 120 km / hr and started at same time . then at what time they meet together .

Answer: 1 pm


Question: Problem: the price of a coat in a certain store is $ 500 . if the price of the coat is to be reduced by $ 400 , by what percent is the price to be reduced ?

Answer:
80