SOLUTION: A plane can travel 400 miles against the wind in the same time that it can travel 500 miles with the wind. If the speed of wind was 10 miles per hour. Find the speed of the plane i
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Question 145406: A plane can travel 400 miles against the wind in the same time that it can travel 500 miles with the wind. If the speed of wind was 10 miles per hour. Find the speed of the plane in still air. Answer by ankor@dixie-net.com(22740) (Show Source):
You can put this solution on YOUR website! A plane can travel 400 miles against the wind in the same time that it can travel 500 miles with the wind. If the speed of wind was 10 miles per hour. Find the speed of the plane in still air.
:
Let s = speed of plane in still air
then
(s-10) = speed against the wind
and
(s+10) = speed with the wind
;
write a time equation; Time =
:
Against time = with time =
Cross multiply
:
500(s-10) = 400(s+10)
:
500s - 5000 = 400s + 4000
:
500s - 400s = 4000 + 5000
:
100s = 9000
s
s = 90 mph in still air
:
:
Check solution by finding the distance
5(90-10) = 400
5(90+10) = 500
