<PRE><B>Question 934770</B>
It took a small plane 2 h longer to fly 375 mi against the wind than it took the plane to fly the same distance with the wind. the rate of the wind was 25 mph. find the rate of the plane in calm air.
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Against wind DATA:
time = x+2 hrs ; distance = 375 miles ; rate = d/t = 375/(x+2) mph
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With wind DATA:
time = x hrs ; distance = 375 miles ; rate = d/t = 375/x mph
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Equation:
Against wind:: p-25 = (375/(x+2))
With wind:: p + 25 = 375/x
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Subtract and solve for &quot;x&quot;::
375/x - 375/(x+2) = 50
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375(x+2) - 375x = 50x(x+2)
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750 = 50x^2 + 100x
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x^2 + 2x - 15 = 0
(x+5)(x-3) = 0
Positive solution::
x = 3 hrs
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Rate of plane in calm air = 375/x = 375/3 = 125 mph
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Cheers,
Stan H.
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