Question

A light plane can fly at a rate of 100 mph in calm air. Traveling with the plane flew 360 mi in the same amount of time as it flew 240 mi against the wind. Find the rate of the wind.

Answer 1

The rate of wind is 20 mph.

Explanation:

The actual speed of the plane is 100 mph.

Now, it is given that, the plane takes the same time to travel 360 miles with the flow of air and to travel 240 miles against the flow of air.

Let the equal time is t hrs.

If, the speed of the plane is u and that of wind is v then we can write,

360/t =u+v ....(1) and

240/t =u-v .....(2)

Now, adding (1) and (2), we get, 2u =600/t, ⇒ 2×100 =600/t, ⇒t = 3 hours.

Hence, from equation (2), we get v = u-240/t, ⇒ v =100-240/3 =20 mph

Therefore, the rate of wind is 20 mph. (Answer)