A car averages 35 miles per hour for the first 4 hours of a trip and averages 53 miles per hour for each additional hour of travel time. If the average speed for the entire trip is 50 miles per hour, how many hours long is the trip?  Choose one: A) 16 B) 18 C) 20 D) 22 E) 24
Let T be the total time of the trip.   35*4 + 53(T-4) = 50T   3T = 212-140   T = 24   The answer is 24.
<result>E</result>
A car averages 35 miles per hour for the first 4 hours of a trip and averages 53 miles per hour for each additional hour of travel time. If the average speed for the entire trip is 50 miles per hour, how many hours long is the trip?