Answer:
V=390mph and W=30mph
Explanation:
Let V be the speed of the airplane and W the speed of the wind.
We have two travels and the formula v=d/t:
V+W=630miles/1.5hr (With the wind)
V-W=630miles/1.75hr (agains the wind)
Clear V from the 1st equation. V=(630/1.5)-W
And replace it into the 2nd equation:
(630/1.5)-W-W=630/1.75
420-2W=360
420-360=2W
W = 60/2
W = 30mi/hr is the wind speed.
Now, we can find V using one equation:
V=(630/1.75)+30 = 360+30
V=390mi/hr is the speed of the airplane.