Question 936772
Find the mph for both trips. Make the plane x and the wind y. So if the plane travels with the wind, it goes 390 mph. x+y=390. If the plane travels against the wind, it goes 310 mph. 310=x-y.

do x+y=390
 - x-y=310
2y= 80, so y or the wind speed is 40mph. and the plane speed is 350 mph.