Question

Alain runs one mile in 9 minutes this year, while he was able to run one mile in 7.5 minutes last year. By what percent did his time decrease?

Answer 1

17%

Explanation:

Divide 7.5 by 9, and then you get 0.833..., round the last digit to the closest thousandth, so you have 83. Subtract 83 from 100, and BOOM! 17! Correct me if I'm wrong!