Question 48328
First, i think you mean 1120km?


DEFINITION: Let x be the speed of the plane
DEFINITION: Let y be the speed of the wind


travelling with the wind, the speed will be x+y and is equal to 1120/7
--> x+y = 160


travelling against the winde, the speed of the plane will be x-y and this is equal to 1120/8
--> x-y = 140


So,
x+y = 160
x-y = 140


Add these together to give 2x = 300
--> x = 150km/hr


From x+y = 160 we get
150+y = 160
y = 10km/hr


jon