SOLUTION: An airplane flew for 3 hours with a 20mph tail wind. The return flight against the same wind took 4 hours. Find the speed of the plane in still air.
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Question 872880: An airplane flew for 3 hours with a 20mph tail wind. The return flight against the same wind took 4 hours. Find the speed of the plane in still air.
You can put this solution on YOUR website! plane speed x mph
wind speed 20 mph
..
against wind x- 20
with wind x+ 20
..
against wind 4 hours
with wind 3 hours
Distance is same. D=r*t
4 ( x - 20 ) = 3 ( x + 20 )
4 x - 80 = 3 x + 60
4 x - 3 x = 80 + 60
1 x = 140
/ 1
x = 140 mph
plane speed = 140 mph
