Problema Solution

A plane has a cruising speed of

100

miles per hour when there is no wind. At this speed, the plane flew

600

miles with the wind in the same amount of time it flew

400

miles against the wind. Find the speed of the wind.

what is the speed of the wind?

Answer provided by our tutors

let


w = the speed of the wind, w>0


v = 100 mph the speed of the plane in still air


since speed = distance/time we have:


traveling against the wind the speed of the plane is: v - w = 100 - w


traveling with the wind the speed of the plane is: v + w = 100 + w


since speed = distance/time we have time = distance/speed


At this speed, the plane flew 600 miles with the wind in the same amount of time it flew 400 miles against the wind:


600/(100 + w) = 400/(100 - w)


by solving we find:


w = 20 mph


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the speed of the wind is 20 mph.