Suzy normally needs 40 minutes to drive home from work.During rush hour,she needs 60 minutes.By what percent does her travel increase during rush hour?

Question

I have a weird answer

Answer 1

travel TIME increases from 40 by 20 to 60 min, at rush hour.

the amount of increase compared to the base (normal) is 20/40 = 0.50 = 50%