Answer: the speed of the plane in still air is 135 km/h
the speed of the wind is 23 km/h
Step-by-step explanation:
Let x represent the speed of the plane in still air.
Let y represent the speed of the wind.
Flying to England with a tailwind a plane averaged 158km/h. This means that the total speed of the plane is (x + y) km/h. Therefore,
x + y = 158 - - - - - - - - - - - - - -1
On the return trip, the plane only averaged 112 km/h while flying back in the same wind. This means that the total speed of the plane is (x - y) km/h. Therefore,
x - y = 112 - - - - - - - - - - - - - -2
Adding equation 1 to equation 2, it becomes
2x = 270
x = 270/2 = 135 km/h
Substituting x = 135 into equation 2, it becomes
135 - y = 112
y = 135 - 112
y = 23 km/h
