An airplane flew 4 hours with a 25 mph tail wind. The return trip against the same wind took 5 hours. How do you find the speed of the airplane in still air?
2 Answers
The speed of the plane is 225 mph.
Explanation:
To solve this task you can use the following system of equations:
Both equations come straight from the laws of cinematics (time equals distance divided by speed)
If you multiply both equations by the denominators you will get:
So you can write only one equation with the unknown
Answer: The speed of the plane without the wind is
Check:
First we calculate the distance:
Next we check the times:
a) with the wind
b) against the wind
I found
Explanation:
Call the speed of the plane (in still air)
and:
from the first equation:
substitute into the second: