Here's another way to do this:
D/R = Time [ in hours] so
Call the rate of the wind, w and the plane's normal rate, p
So we have.....when the plane is flying with the wind.....
460/ [p + w] = 2
230/[p+ w] = 1
230 = p + w
p = 230 - w
And when the plane is against the wind, we have
460 / [p - w] = 2.5
184 / [ p - w] = 1 subbing in for p, we have
184/ [ 230 - w - w] = 1
184 = 230 - 2w
2w = 230 - 184
2w = 46
w = 23 mph
And the plane's normal rate = 230 - 23 = 207 mph
