Question 1192916: When a plane flies with the wind, it can travel 1680 miles in 4 hours. When the plane flies in the opposite direction, against the wind, it takes 5 hours to fly the same distance. Find the rate of the plane in still air and the rate of the wind.
The rate of the wind is ____ miles per hour.
Found 2 solutions by Alan3354, Edwin McCravy:
Answer by Alan3354(69443)   (Show Source):
You can put this solution on YOUR website! When a plane flies with the wind, it can travel 1680 miles in 4 hours. When the plane flies in the opposite direction, against the wind, it takes 5 hours to fly the same distance. Find the rate of the plane in still air and the rate of the wind.
The rate of the wind is ____ miles per hour.
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Find the 2 groundspeeds, downwind and upwind.
The plane's airspeed is the average of the 2.
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Windspeed = difference between airspeed and groundspeed.
Answer by Edwin McCravy(20054)  (Show Source):
You can put this solution on YOUR website!
Make this chart. Let r = rate in still air, and
let w = the rate of the wind.
| Rate | Time | Distance
-----------------------------------------
With the wind | r+w | 4 | 1680
-----------------------------------------
Against wind | r-w | 5 | 1680
Rate x Time = Distance
(r+w)(4) = 1680
(r-w)(5) = 1680
Divide the first through by 4 and the
second through by 5:
Add those two equations term by term, and the w's will cancel
and you can find r. Then substitute to find w.
Edwin
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