SOLUTION: A plane traveled 624 miles to Perth and back. The trip there was with the wind. It took four hours. The trip back was into the wind. The trip back took 6 hours. What is the speed o

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Question 535026: A plane traveled 624 miles to Perth and back. The trip there was with the wind. It took four hours. The trip back was into the wind. The trip back took 6 hours. What is the speed of the plane in still air? What is the speed of the wind?
I really need help on this one and would be so greatful to anyone that would show me the answer.
Answer by mananth(16946) About Me  (Show Source):
You can put this solution on YOUR website!
plane speed =x mph
wind speed speed =y mph
against current x-y 6.00 hours
With current x+y 4.00 hours

Distance = same= 624 miles
t=d/r
624 / ( x - y )= 6.00
6 ( x - y ) = 624.00
6 x -6 y = 624 ....................1
624 / ( x + y )= 4.00
4.00 ( x + y ) = 624
4.00 x + 4.00 y = 624 ...............2
Multiply (1) by 2.00
Multiply (2) by 3.00
we get
12 x + -12 y = 1248
12 x + 12 y = 1872
24 x = 3120
/ 24
x = 130 mph

plug value of x in (1)
6 x -6 y = 624
780 -6 y = 624
-6 y = 624 -780
-6 y = -156
y = 26 mph
plane 130 mph
wind speed 26 mph
m.ananth@hotmail.ca