A pilot flew a 400-mile flight in 2.5 hours flying into the wind. Flying the same rate and with the same wind speed, the return trip took only 2 hours, with a tailwind.What was the speed of the wind?

The speed into the wind was 400 ÷ 2.5 = 160 miles per hour, and the speed with the tailwind was 400 ÷ 2 = 200 miles per hour. The difference, 200 − 160 = 40, is twice the wind speed because the wind slows the plane on the outbound trip and speeds it up by the same amount on the return. So the wind speed was 40 ÷ 2 = 20 miles per hour, choice A.

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