Question

A plane flies 540 miles for 2 hours in the direction of the wind. Then it turns around and flies 690 miles
for 3 hours against the same wind. Find the speed of the plane in still air and the wind speed.

Answer 1

speed of plane in still air --- x mph
speed of wind ------ y mph

rate into the wind = x-y
rate with the wind = x+y

2(x+y) = 540
x + y = 270

3(x-y) = 690
x-y = 230
add them:
2x = 500
x = 250
then y = 20