Sarawong drove to the lake and back. The trip there took two hours and the trip back took three hours.

Question

Sarawong drove to the lake and back. The trip there took two hours and the trip back took three hours. He averaged 20 mph faster on the trip there than on the return trip. What was sarongs average speed on the outbound trip?

***

Note: Please provide a thorough and in-depth explanation as to how you arrive to the conclusion.

Answer 1

d = 2 * R = 3 * (R-20)

2R = 3r - 60

0 = r - 60

r = 60

2 * 60 = 120

3 * 40 = 120 <--- 20 mph slower for 3 hours