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A plane flies 465 miles with the wind and 315 miles against the wind in the same length of time. If the speed of the wind is 25 ​mph, find the speed of the plane in still air.

 Feb 10, 2020
 #1
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+1

If the speed of the wind is 25 mph, then the plane's speed against the wind must be 415 mph, NOT 315 mph !!

 

[465  +  415] / 2 =440 mph - its speed in still air.

[465  -  415] / 2 =25 mph - the speed of the wind.

 Feb 10, 2020
 #2
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465(x-25) = 315(x+25)

        150x = 19500

              x = 130

laugh

 Feb 10, 2020

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