9514 1404 393
Answer:
Step-by-step explanation:
The speed against the wind is ...
4680 mi/(8 h) = 585 mi/h
The speed with the wind is ...
5720 mi/(8 h) = 715 mi/h
The speed of the airplane in still air is the average of these speeds:
(585 +715)/2 = 650 mi/h . . . speed in still air
The speed of the wind is the difference between the airplane speed and the speed in the wind:
715 -650 = 65 mi/h . . . speed of the wind
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<em>Additional comment</em>
If p and 'a' represent the speeds of the plane and the air, the speeds with and against the wind are ...
p + a = with
p - a = against
If we average these, we get ...
((p +a) +(p -a))/2 = (with + against)/2
p = (with + against)/2 . . . . . . . the formula we used above
