Answer:
22.5 miles per hour
Explanation:
Given system of equations
5(s-w)=900
4(s+w)=900
Set equations equal to each other
5(s-w)=4(s+w)
5s-5w=4s+4w
s-5w=4w
s=9w
Solve for w using the substitution s=9w
4(s+w)=900
4(9w+w)=900
4(10w)=900
40w=900
w=22.5
Therefore, the speed of the wind is 22.5 miles per hour