Solve.
-A plane flies 420 miles with the wind and 300 miles against the wind in the same length of time. If the speed of the wind is 29 mph, what is the speed of the plane in still air?
A)164 mph
B)179 mph
C)199 mph
D)174 mph

Question

Quizplus · Accepted Answer

The speed of the plane in still air can be found by setting up the equation for time, which is distance divided by speed. Let $ p $ be the speed of the plane in still air and $ w $ be the speed of the wind, which is given as 29 mph. With the wind, the plane's speed is $ p + w $, and against the wind, the plane's speed is $ p - w $. Since the times are equal, we have $\frac{420}{p + 29} = \frac{300}{p - 29}$. Solving this equation for $ p $ gives us the speed of the plane in still air as 174 mph.

Solve. -A Plane Flies 420 Miles with the Wind and 300