An airplane travels 400 miles against the wind in 5 hours an

An airplane travels 400 miles against the wind in 5 hours, and makes the return trip with the same wind in 2hours. Find the speed of the wind.

Solution

Equations:
Let \"p\" be speed of the plane in still air
Let \"w\" be speed of the wind
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p + w = 200
P - w = 80
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Add the two equations to solve for \"p\":
2p = 280
p = 140 mph (speed of the plane in still air)
---Substitute into P+w = 200 to solve for \"w\"
140 + w = 200
w = 60 mph (speed of the wind)