Question

the costs of two sound systems were decreased by $10. the original costs of the systems were $90 and $60. without calculating, which had a greater percent decrease? explain

Answer 1

Without calculating we can say that the system with the original cost $60 ( the cheaper system ) had a greater percent decrease.
This is because $10 is a greater percentage of $60 than it is of $90 ( if we calculate it is 16.66% in the first case and 11.11% in the second case).