SOLUTION: An airplane can fly with the wind a distance of 900 miles in 3 hours. However, the return trip against the wind takes 5 hours. Find the speed of the plane in still air and the spee

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Question 931150: An airplane can fly with the wind a distance of 900 miles in 3 hours. However, the return trip against the wind takes 5 hours. Find the speed of the plane in still air and the speed of the wind.

Answer by mananth(16946) About Me  (Show Source):
You can put this solution on YOUR website!
plane speed =x mph
wind speed =y mph
against wind 5 hours
with wind 3 hours

Distance with wind 900 miles distance against wind 900
t=d/r against wind (x-y)
900.00 / ( x - y )= 5.00

5.00 x - -5.00 y = 900.00 ....................1
with wind (x+y)
900.00 / ( x + y )= 3.00
3.00 ( x + y ) = 900.00
3.00 x + 3.00 y = 900.00 ...............2
Multiply (1) by 3.00
Multiply (2) by 5.00
we get 2.00
15.00 x + -15.00 y = 2700.00
15.00 x + 15.00 y = 4500.00
30.00 x = 7200.00
/ 30.00
x = 240.00 mph

plug value of x in (1) y
5.00 x -5.00 y = 900.00
1200.00 -5.00 -1200.00 = 900.00
-5.00 y = 900.00
-5.00 y = -300.00 mph
y = 60.00
plane 240.00 mph
wind 60.00 mph