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Flying against the wind, an airplane travels 3850 km in 7 hours. Flying with the wind, the same plane travels 4350 km in 5 hours. What is the rate of the plane in still air and what is the rate of the wind?

Mar 21, 2020

#1
+111329
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Flying against the wind, an airplane travels 3850 km in 7 hours. Flying with the wind, the same plane travels 4350 km in 5 hours. What is the rate of the plane in still air and what is the rate of the wind?

Let P  be the plane's rate in still air

Let the rate  of the wind   = W

So  we  have  that  Time *  Rate   = Distance

So

7(P - W)  = 3850     divide  both sides  by  7

5(P + W)  =  4350   divide both sides  by 5

P - W   =  550

P + W =  870      add these

2P  = 1420     divide both sides  by 2

P  =  710  (kph)

And

710  - W =  550

W =  710 - 550

W = 160 [kph]

That's a STRONG WIND   !!!!

Mar 21, 2020
#2
+1968
+2

LOL!!!!!!! Anyway, here's another way to do it.

x=Plane's rate in still air

y= Rate of the wind

x-y=550

x+y=870

Then, use the elimination method. (subtract)

-2y=-320

y=160km/h

Then, we know that the plane's rate in still air is 550+160, which is 710 km/h.

It is DEFINITELY A STRONG WIND!!!!!!!

CalTheGreat  Mar 21, 2020
edited by CalTheGreat  Mar 21, 2020