SOLUTION: 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 w

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Question 201088: 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?
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Let w = wind speed
Let s = speed of plane in calm air
Let t = time for both trips
given:
s+=+180
With the wind:
7+=+%28180+%2B+w%29%2At
5+=+%28180+-+w%29%2At
--------------------
7+=+180t+%2B+wt
5+=+180t+-+wt
Add the equations
12+=+360t
t+=+1%2F30 hrs
and, since
5+=+%28180+-+w%29%2At
5+=+%28180+-+w%29%2A%281%2F30%29
150+=+180+-+w
w+=+180+-+150
w+=+30
The windspeed is 30 mi/hr