<PRE><B>Question 966234</B>
A plane can fly at a rate of 215 mph in calm air. Traveling with the wind, the plane flew 750 miles in the same amount of time it took to fly 540 miles against the wind. Find the rate of the wind.
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let c=rate of wind
215+c=rate of plane with wind
215-c=rate of plane against wind
travel time=distance/rate (same for both planes)
..
750/(215+c)=540/(215-c)
cross multiply:
540(215+c)=750(215-c)
116100+540c=161250-750c
1290c=45150
c=35
rate of wind=35 mph
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