SOLUTION: An airplane flew for 4 hours against a head wind of 40 km/h. On the return flight the same wind was now a tail wind, and the flight took 4 hours. find the speed of the airplane in

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Question 30288: An airplane flew for 4 hours against a head wind of 40 km/h. On the return flight the same wind was now a tail wind, and the flight took 4 hours. find the speed of the airplane in still air.
Answer by Paul(988) About Me  (Show Source):
You can put this solution on YOUR website!
Let the speed of the plane be x
Equation:
x%2F4%2Bx%2F4=40
Multiply the whole equation by 4 to remove the fraction and simplify:
2x=160
x=80

Hence, the speed of the plane in still air is 80mph.
Paul.