If a plane can travel 210 miles per hour with the wind and only 190 miles per hour against the wind, find the speed of the wind and the speed of the plane in still air.
A) Plane: $300 \mathrm{mph}$, wind: $10 \mathrm{mph}$
B) Plane: $10 \mathrm{mph}$, wind: $200 \mathrm{mph}$
C) Plane: $200 \mathrm{mph}$, wind: $20 \mathrm{mph}$
D) Plane: $200 \mathrm{mph}$. wind: $10 \mathrm{mph}$

Question

Quizplus · Accepted Answer

The speed of the plane in still air is the average of the speeds with and against the wind: $(210 + 190) / 2 = 200 \mathrm{mph}$. The wind speed is the difference between the plane's speed with the wind and the speed in still air: $210 - 200 = 10 \mathrm{mph}$.

If a Plane Can Travel 210 Miles Per Hour with the Wind