SOLUTION: a small plane cruises at 180 mph. it takes the same amount of time to travel 7 miles with the wind as it takes to travel 5 miles against the wind. what is the wind speed?
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Question 271882: a small plane cruises at 180 mph. it takes the same amount of time to travel 7 miles with the wind as it takes to travel 5 miles against the wind. what is the wind speed? Answer by dabanfield(803) (Show Source):
You can put this solution on YOUR website! a small plane cruises at 180 mph. it takes the same amount of time to travel 7 miles with the wind as it takes to travel 5 miles against the wind. what is the wind speed?
Let w be the wind speed and t the time traveled. Then using distance = rate*time we have:
1.) 7 = (180+w)*t (with the wind)
2.) 5 = (180-w)*t (against the wind)
Expanding we have:
From 1.) we have t = 7/(180+w)
Substituting 7/(180+w) for t in 2.) we have:
5 = (180-w)*(7/(180+w))
Multiply both sides above by (180+w):
5*(180+w) = (180-w)*7
900+5w = 1260-7w
Solve the above for w.
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