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

[Q]: Problem: when the price of a product was decreased by 20 % , the number sold increased by 60 % . what was the effect on the total revenue ?
[A]: 28 %


[Q]: Problem: by investing in 1623 % stock at 64 , one earns rs . 1500 . the investment made is
[A]: rs . 5760


[Q]: Problem: if the length of the sides of two cubes are in the ratio 6 : 1 , what is the ratio of their total surface area ?
[A]:
36 : 1