Question

Flying against the wind, an airplane travels 2520 kilometers in 4 hours. Flying with the wind, the same plane travels 3390 kilometers in 3 hours. What is the rate of the plane in still air and what is the rate of the wind?

Answer 1

Explanation:

Let the speed of the plane = p

Let the speed of the wind = w

Time against the wind = 4 hours

distance against the wind = 2520 km

distance with the wind = 3390 km

time with the the wind = 3 hours

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equations

With the wind.

(p + w)* t = d1

Against the wind =

(p-w)*t1 = d2

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(p - w)*4 = 2520

(p + w)*3 = 3390

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divide the top equation by 4

(p - w) = 2520/4

p - w = 630

divide the bottom equation by 3

p + w = 3390/3

p + w = 1130

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Now to find the answers

p - w = 630

p + w = 1130 Add

2p = 1760 Divide by 2

p = 880 So the plane is going 880 km / hr. with no influence of the wind.

p + w = 1130

880 + w = 1130

w = 1130 - 880

w = 250 km / hour

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p = 880

w = 250