SOLUTION: A plane makes a trip 5040 km in 7 h, flying with the wind. Returning against the wind , the plane makes the trip in 9 h. What is the speed of the wind?

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Question 326185: A plane makes a trip 5040 km in 7 h, flying with the wind. Returning against the wind , the plane makes the trip in 9 h. What is the speed of the wind?
Answer by Fombitz(32388) About Me  (Show Source):
You can put this solution on YOUR website!
Let P be the plane speed in still air, W the wind speed.
%28P%2BW%297=5040
1.P%2BW=720
.
.
.
%28P-W%299=5040
2.P-W=560
Add eq. 1 to eq. 2 to eeliminate W.
P%2BW%2BP-W=1280
2P=1280
P=640kph
Then use either equation to solve for W,
640%2BW=720
W=80kph