Question

Flying with wind, a plane flew 800 miles in 5 hrs. Flying against the wind, the plane flew the same distance in 8 hrs. Find the still air speed and wind speed.

Answer 1

If the plane's air speed is s, and the wind speed is w

800/(s+w) = 5
s+w = 160

800/(s-w) = 8
s-w = 100

2s=260
s=130
so, w=30

800/160 = 5
800/100 = 8

Answer 2

What's the 2s equation ??