John rode his new bicycle at 9 miles per hour. How many feet per hour is this?
(Hint: Since 1 mile = 5,280 feet, multiply by 5,280 feet/1 mile.)
Oa. 47,520 feet per hour
Oc. 5,280 feet per hour
Ob. 45,720 feet per hour
O d. 52,380 feet per hour