<PRE><B>Question 505826</B>
If a plane can travel 380 miles per hour with the wind and only 280 miles per hour against the wind, find the speed of the wind and the speed of the plane in still air

Let
Speed of wind = w
Speed of Plane= p

Speed with the wind
Speed (wind + plane) = 380 
w+p=380 .............(1)


Speed against the wind
Speed (plane - wind)= 280
p-w=280 ................(2)

Add (1) and (2)

w+p=380 
p-w=280 
---------
2p=660
Divide by 2 both sides of above equation, we have

2p/2=660/2
p=330

Put the value of p in (1)
 
w+p=380
w+330=380

w=380-330
w=50


Speed of wind = w = 50 mph
Speed of Plane= p = 330 mph
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