-- Posted by CaptainUnderpants at 5:02 pm on May 30, 2008 A plane can fly 480 miles per hour (mph) when there is no wind. If there is wind blowing at a constant rate, the plane can fly 618 miles downwind in the same amount of time it can fly 534 miles upwind. Find the speed of the wind. Hint: when flying downwind, the speed of the plane increases by the amount of the windspeed. When flying upwind, the plane's speed decreases by the same amount. -- Posted by Khadgar at 5:06 pm on May 30, 2008 You know that the plane could travel 618 miles at the downwind speed in the same time that it could travel 534 miles at the upwind speed. The speed of the plane with no wind is 480 miles an hour, so lets let the speed of the wind be x. Therefore, the speed of the plane downwind is 480 + x, and the speed of the plane upwind is 480 - x. 618 / (480 + x) = 534 / (480-x) Solve for x. -- Posted by CaptainUnderpants at 5:07 pm on May 30, 2008 Quote: from Khadgar at 8:06 pm on May 30, 2008 618____-color=green==_____534 (480 + x)__(480-x) thanks a fuckin lot. -- Posted by Khadgar at 5:16 pm on May 30, 2008 Continuing, 534(480 + x) = 618(480 - x) 256320 + 534x = 296640 - 618x 1152x = 40320 x = 35 The speed of the wind is 35 miles per hour.