SOLUTION: A plane flies 480 miles with the wind in 4 hours. Returning against the wind, takes 6 hours. What is the rate of the plane in still air?

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Question 999800: A plane flies 480 miles with the wind in 4 hours. Returning against the wind,
takes 6 hours. What is the rate of the plane in still air?
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 6 hours
with wind 4 hours

Distance against 480 miles distance with 480 miles
t=d/r against wind -
480 / ( x - y )= 6
6 ( x - y ) = 480
6 x - 6 y = 480 ....................1

480 / ( x + y )= 4.00
4.00 ( x + y ) = 480
4.00 x + 4.00 y = 480 ...............2
Multiply (1) by 4
Multiply (2) by 6 24
we get
24.00 x + -24 y = 1920
24.00 x + 24 y = 2880
48 x = 4800
/ 48
x = 100 mph

plug value of x in (1)
6 x -6 y = 480
600 -6 y = 480
-6 y = 480 -600
-6 y = -120 mph
y = 20
Plane speed 100 mph
wind speed 20 mph

m.ananth@hotmail.ca