SOLUTION: Show a complete solution to each problem. Big Plane. A six passenger plane cruises at 180 mph in calm air. If the plane flies 7 miles with the wind in the same amount of time as i

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Question 46652: Show a complete solution to each problem.
Big Plane. A six passenger plane cruises at 180 mph in calm air. If the plane flies 7 miles with the wind in the same amount of time as it flies 5 miles against the wind then what is the wind speed?

Thanks
Answer by adamchapman(301) About Me  (Show Source):
You can put this solution on YOUR website!
Finally, a question about aeroplanes!
Let the windspeed be called "w" and the time taken be called "t".
We know that the time taken for the plane to cover a certain distance is equal to its speed divided by that distance.
We can now write two equations:
%28180%2Bw%29%2F7=t (with the wind)
%28180-w%29%2F5=t (against the wind)
Notice how both equations are equal to "t". This means we can say:
%28180%2Bw%29%2F7=%28180-w%29%2F5
Now rearrange to find "w":
5%28180%2Bw%29=7%28180-w%29
900%2B5w=1260-7w
12w=360
w=360%2F12=30
So the wind speed is 30mph.
I hope this helps,
Adam.
P.S. please visit mt website, it might be useful to you. The address is http://www.geocities.com/quibowibbler