Solve the problem.
-On a recent trip, Sarah's car traveled 20 mph faster on the first 200 miles than it did on the remaining 80 miles. The total time for the trip was 4 hr. Find the speed of Sarah's car on the first part of the trip.
A) 68 mph
B) 57 mph
C) 77 mph
D) 13 mph

Question

Quizplus · Accepted Answer

Let the speed on the first part be x mph. Then, the speed on the second part is (x - 20) mph. The time for the first part is 200/x hours, and for the second part is 80/(x - 20) hours. The total time is 4 hours: 200/x + 80/(x - 20) = 4. Solving this equation gives x = 77 mph.

Solve the Problem. -On a Recent Trip, Sarah's Car Traveled 20 Mph Faster