Question 268325
With the wind a jet can fly 2500km in 2 hours 30 min.
With wind DATA: 
distance = 2500 km ; time = 2.5 hrs ; rate = 2500/2.5 = 100 kmh
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Against the wind, it can fly only 2000km in the same time.
Against wind DATA:
distance = 2000 km ; time = 2.5 hrs ; rate = 2000/2.5 = 800 kmh
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Find the rate of the jet in still air and the rate of the wind.
p + w = 100
p - w = 80
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2p = 180
p = 90 kmh (plane speed in still air)
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Since p+w = 100, w = 10 kmh (wind speed)
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Cheers,
Stan H.