<PRE><B>Question 254673</B>
Airline Schedules allow 3 hours and 10 minutes airborne time to fly from Washington D.C to Dallas 
and 2 hours and 15 minutes from Dallas to Washington D.C.
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The Time difference can largely be attributed to the jet stream, a wind that usually blows from west to east.
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The distance between Washington d.C and Dallas is 1176 miles.
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What is the speed of the jet stream? what is the speed of the plane in still air.
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DC to DALLAS DATA:
distance = 1176 miles ; time = 3 1/6 hrs ; rate = 1176/(19/6) mph
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DALLAS to DC DATA:
distance = 1176 miles ; time = 2 1/4 hrs ; rate = 1176/(9/4) mph
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Equations:
plane + wind = 1176/(9/4)
Plane - wind = 1176/(19/6)
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Add and solve for plane speed:
2p = 1176/(9/4) + 1176/(19/6)
p = 588/(9/4) + 588/(19/6)
p = 261 1/3 + 185.68
p = 447.02 mph (rate of the plane in still air)
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Substitute into p+w = 1176/(9/4) to solve for &quot;w&quot;:
447.02 + w = 1176/(9/4)
w = 75.65 mph (rate of the wind)
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Cheers,
Stan H.

 
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