Susan can solve 8 math problems in 20 minutes while Betsy can solve the same 8 math problems at a rate of 1 problem per 5 minutes. Who works faster? Show your work.
Susan works faster if you solve 8 problems in 20 minutes, that is faster than 1 problem per minute because even once you do 5 problems you are at 25 minutes and that is longer than the 20 minutes