Question 476440
with a strong wind behind it, a United Airlines jet flies 2400 miles from Los Angeles to Orlando in 4 3/4 hours.
 The return trip takes 6 hours, as the plane flies into the wind. 
Find the speed of the plane in still air, and find the wind speed to the nearest tenth of a mile per hour.
:
Let s = plane speed in still air
Let w = speed of the wind
:
Write two distance equations: dist = time * speed
:
4.75(s+w) = 2400
and
6(s - w) = 2400 
6s - 6w  = 2400
Simplify, divide be 6
s - w = 400
s = (w+400)
:
In the 1st equation replace s with (w+400)
4.75(w + 400 + w) = 2400
4.75(2w + 400) = 2400
9.5w + 1900 = 2400
9.5w = 2400 - 1900
9.5w = 500
w = {{{500/9.5}}}
w = 52.6 mph is speed of the wind
:
Find s using s = w + 400
s = 52.6 + 400
s = 452.6 mph is the speed of the plane in still air
:
:
Check this this in the 2nd equation
6(452.6 - 52.6) = 
6(400) = 2400