SOLUTION: Big plane. A six-passenger plane cruises at 180 mph in calm air. If the plane flies 7 miles with the wind in the same amount of time as it flies 5 miles against the wind, then w

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Question 203473This question is from textbook
: Big plane. A six-passenger plane cruises at 180 mph in
calm air. If the plane flies 7 miles with the wind in the
same amount of time as it flies 5 miles against the wind,
then what is the wind speed? This question is from textbook

Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
You can put this solution on YOUR website!
A six-passenger plane cruises at 180 mph in calm air.
If the plane flies 7 miles with the wind in the same amount of time
as it flies 5 miles against the wind, then what is the wind speed?
:
Let w = speed of the wind
then
(180+w) = plane speed with the wind
and
(180-w) = plane speed against the wind
:
The time of the two trips is equal, write a time equation
Time = dist%2Fspeed
:
7 mi time = 5 mi time
7%2F%28%28180%2Bw%29%29 = 5%2F%28%28180-w%29%29
Cross multiply
7(180-w) = 5(180+w)
:
1260 - 7w = 900 + 5w
:
1260 - 900 = 5w + 7w
:
360 = 12w
w = 360%2F12
w = 30 mph is the speed of the wind
:
:
Check solution by finding the times, are they equal(210 with, 150 against)
7/210 = .033
5/150 = .033