velocity of plane is given as
[tex]\vec v_p = 250 \hat i[/tex]
velocity of air
[tex]\vec v_a = -25\sqrt 2\hat i - 25\sqrt2 \hat j + 30 \hat k[/tex]
now the net speed of the plane is given as
[tex]v = v_p + v_a[/tex]
[tex]v = 250 \hat i - 25\sqrt 2\hat i - 25\sqrt 2\hat j + 30 \hat k[/tex]
[tex]v = 214.6 \hat i - 35.35\hat j+ 30\hat k[/tex]
now the net speed is
[tex]v = \sqrt{214.6^ + 35.5^2 + 30^2}[\tex]
[tex]v = 219.55 mi/hr[/tex]
so above is the net speed of the plane