Brook drove a total of 180 miles in 3 hours. diederick drove a total of 160 miles in 4 hours.

which explanation correctly describes a way to calculate how many miles per hour faster brook drove than diederick?

Actually, DIEDERICK drove faster than BROOK. What you can do to find out the answer, is divide. Brook drove 180 miles in 3 hours, so divide 180 by 3, and you get 60. If you divide 160 by 4, you get 40. So, that means that Diederick drove faster than Brook.