Question 715327
 Flying against the wind, an airplane travels 1800 km in 3 hours. Flying with the wind, the same plane travels 5740 km in 7 hours. What is the rate of the plane in still air and what is the rate of the wind? 
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Against DATA:
distance = 1800 km ; time = 3 hrs ; rate = d/t = 1800/3 = 600 km/hr
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With DATA:
distance = 5740 km ; time = 7 hrs ; rate = d/t = 5740/7 = 820 km/hr
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Equation:
Against: p - w = 600
With:::: p + w = 820
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Add and solve for "p":
2p = 1420
p = 710 km/hr (speed of the plane in still air)
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Solve for "w":
Subtract one equation from the other and solve for "w":
2w = 120
w = 60 km/hr (speed of the wind)
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Cheers,
Stan H.
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