SOLUTION: A plane flies 900 miles with a tail wind in 3 hours.It takes the same plane 2 hours to fly the 300 miles when flying against the wind. What is the plan's speed in still air?
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Question 459117: A plane flies 900 miles with a tail wind in 3 hours.It takes the same plane 2 hours to fly the 300 miles when flying against the wind. What is the plan's speed in still air? Answer by oberobic(2304) (Show Source):
You can put this solution on YOUR website! The basic distance equation is:
d = rt
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We are told that flying with the tailwind
900 = r*3
r = 300
BUT
r = speed of the plane + speed of the tailwind
.
We are told flying with the headwind
300 = r*2
r = 150
BUT this time,
r = speed of the plane - speed of the wind
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Assuming the wind is constant...which is important.
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We can define:
s=speed of the plane
w=speed of the wind
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Substitute what we know:
s+w = 300
s-w = 150
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Add the linear equations.
2s = 450
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Solve for s
s = 225
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Substitute to solve for w
w = 75
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Check by substituting these value to see if you get the correct distance.
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3(225+75) = ??
3(300) = 900
Right
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2(225-75) = ??
2(150) = 300
Right
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Re-read the question to see what answer is required.
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Answer: The plane's speed in still air is 225 miles/hr.
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Done.
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