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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
avatar+111329 
+1

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   !!!!

 

 

cool cool cool

 Mar 21, 2020
 #2
avatar+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

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