Question 1069790: A plane flies 435 miles with the wind and 375 miles against the wind in the same length of time. If the speed of the wind is 10 mph, find the speed of the plane in still air.
Answer by Boreal(15235)   (Show Source):
You can put this solution on YOUR website! in x time, the plane flies 435 miles, so speed is 435/x; that speed is p+10
in x time, the plane flies 375 miles, so speed is 375/x;that speed is p-10
p-10=375/x
x=375/p-10
x also = 435/p+10
set those two equal to each other and cross-multiply
375(p+10)=435 (p-10)
375p +3750=435p-4350
60p=8100
p=135 mph. ANSWER
With the wind, the plane flies at 145 mph and covers 435 miles in 3 hours.
Against the wind, the plane flies at 125 mph and covers 375 miles in 3 hours.
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