A plane flies 420 miles with the wind and 340 miles against the wind in the same length of time. If the speed of the wind is $22 \mathrm{mph}$, what is the speed of the plane in still air?
A) $199 \mathrm{mph}$
B) $209 \mathrm{mph}$
C) $214 \mathrm{mph}$
D) $234 \mathrm{mph}$

Question

Quizplus · Accepted Answer

Let the speed of the plane in still air be $p$ mph. The speed of the plane with the wind is $p + 22$ mph, and against the wind is $p - 22$ mph. Since the times are the same, we can set up the equation $\frac{420}{p + 22} = \frac{340}{p - 22}$. Solving this equation for $p$ gives $p = 209$ mph.

A Plane Flies 420 Miles with the Wind and 340 22mph22 \mathrm{mph}22mph

A Plane Flies 420 Miles with the Wind and 340 $22 \mathrm{mph}$