SOLUTION: An airplane flies 840 mi in 3 hours with a tail wind. The return trip at the same airspeed takes 3.5 hours. Find the wind speed and the airspeed.

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Question 318962: An airplane flies 840 mi in 3 hours with a tail wind. The return trip at the same airspeed takes 3.5 hours. Find the wind speed and the airspeed.
Answer by Fombitz(32388) About Me  (Show Source):
You can put this solution on YOUR website!
Rate*Time=Distance
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Let P be the plane speed, W the wind speed.
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%28P%2BW%293=840<--- with the wind
1.P%2BW=280mph
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%28P-W%293.5=840<--- against the wind
2.P-W=240mph
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Add eq. 1 and eq. 2 to eliminate W,
P%2BW%2BP-W=280%2B240
2P=520
highlight%28P=260%29
Then use either equation to solve for W,
260%2BW=280
highlight%28W=20%29