SOLUTION: A plane traveled 300 miles to Lagos and back. The trip there was with the wind. It took 3 hours. The trip back was into the wind. The trip back took 6 hours. What is the speed
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Question 542512: A plane traveled 300 miles to Lagos and back. The trip there was with the wind. It took 3 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? Please help! Answer by mananth(16946) (Show Source):
You can put this solution on YOUR website! plane speed speed =x mph
wind speed =y mph
against wind , x-y 6 hours
with wind , x+y 3 hours
Distance = same= 300 miles
t=d/r against wind
300 / ( x - y )= 6.00
6 ( x - y ) = 300.00
With wind
6 x -6 y = 300 ....................1
300 / ( x + y )= 3.00
3.00 ( x + y ) = 300
3.00 x + 3.00 y = 300 ...............2
Multiply (1) by 1.00
Multiply (2) by 2.00
we get
6 x + -6 y = 300
6 x + 6 y = 600
12 x = 900
/ 12
x = 75 mph
plug value of x in (1)
6 x -6 y = 300
450 -6 y = 300
-6 y = 300 -450
-6 y = -150
y = 25 mph
plane speed 75 mph
wind 25 mph
