Answer:
wind speed = 90 mi/h
aircraft speed = 810 mi/h
Explanation:
Let the speed of the airplane be u and the wind speed be w.
The distance d traveled is given by: d = speed * time
1. trip:
d = 3600 miles, time t = 4 h, speed = u + w
3600 = (u + w) * 4
2. trip:
d = 3600 miles, time t = 5 h, speed = u - w
3600 = (u -w) * 5
You have two equations with two unknown. Solve for u and w.
For example:
(u + w) * 4 = (u - w) * 5
4u + 4w = 5u - 5w
u = 9w
Plugging this result in one of the equations gives:
3600 = (9w + w) * 4
3600 = 10w * 4
w = 90 mi/h
u = 810 mi/h
