A plane flew 450 miles in 3 hours with the wind. It took 5 hours to travel the same distance against the wind. What is the rate of the plane in still air and the rate of the wind?
A) plane: 150 mph; wind: 90 mph
B) plane: 120 mph; wind: 30 mph
C) plane: 130 mph; wind: 40 mph
D) plane: 130 mph; wind: 30 mph

Question

Quizplus · Accepted Answer

The plane's speed in still air is the average of its speed with the wind and its speed against the wind. With the wind, its speed is 450 miles / 3 hours = 150 mph. Against the wind, its speed is 450 miles / 5 hours = 90 mph. The plane's speed in still air is (150 mph + 90 mph) / 2 = 120 mph. The wind's speed is the difference between the plane's speed with the wind and its speed in still air, which is 150 mph - 120 mph = 30 mph.

A Plane Flew 450 Miles in 3 Hours with the Wind