SOLUTION: a plane can fly 400 miles downwind in the same amount of time as it can travel 320 miles upwind. If the plane can fly at 360 miles per hour in still air. Find the speed of the win

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Question 162653This question is from textbook beginning and intermediate algebra
: a plane can fly 400 miles downwind in the same amount of time as it can travel 320 miles upwind. If the plane can fly at 360 miles per hour in still air. Find the speed of the wind. I need to revise my exam This question is from textbook beginning and intermediate algebra

Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
You can put this solution on YOUR website!
plane can fly 400 miles downwind in the same amount of time as it can travel 320 miles upwind. If the plane can fly at 360 miles per hour in still air. Find the speed of the wind.
:
Let x = speed of the wind
then
(360-x) speed against the wind
and
(360+x) speed with the wind
:
It says the times are equal for flying 400 mi and 320 mi. Write a time equation
time = distance%2Fspeed
:
Time with the wind = time against the wind
400%2F%28%28360%2Bx%29%29 = 320%2F%28%28360-x%29%29
Cross multiply
320(360+x) = 400(360-x)
:
115200 + 320x = 144000 - 400x
:
320x + 400x = 144000 - 114200
:
720x = 28800
x = 28800%2F720
x = 40 mph is the wind
:
:
Check the solution, find out if the times are equal:
Using the wind, the speed with 400, speed against 320
400/400 = 1 hr
320/320 = 1 hr