SOLUTION: a plane flies 400 miles with the wind and 300 miles against the wind in the same length of time. If the speed of the wind is 22 mph, what is the speed of the plane in still air?

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Question 231242: a plane flies 400 miles with the wind and 300 miles against the wind in the same length of time. If the speed of the wind is 22 mph, what is the speed of the plane in still air?
Answer by checkley77(12844) About Me  (Show Source):
You can put this solution on YOUR website!
D=RT or T=D/R
T=400/(R+22)
T=300/(R-22)
400/(R+22)=300/(R-22)
400(R-22)=300(R+22)
400R-8,800=300R+6,600
400R-100R=8,800+6,600
100R=15,400
R=15,400/100
R=154 MPH FOR THE PLANE IN STILL AIR.
PR00F:
400/(154+22)=300/(154-22)
400/176=300/132
400*132=300*176
52,800=52,800