Here when plane is moving in the direction of the wind we can say
[tex]V_{plane} + v_{wind} = \frac{distance}{time}[/tex]
[tex]350 mph + v_{wind} = \frac{1200}{t}[/tex]
now another plane is also moving against the wind
so we can say
[tex]V_{plane} - v_{wind} = \frac{distance}{time}[/tex]
[tex]450 - v_{wind} = \frac{1300}{t}[/tex]
Now from above two equations we will have
divide the two equations
[tex]\frac{350+v_{wind}}{450 - v_{wind}}= \frac{1200}{1300}[/tex]
[tex]4550 + 13v_{wind} = 5400 - 12v_{wind}[/tex]
[tex]25 v_{wind} = 850[/tex]
[tex]v_{wind} = 34 mph[/tex]