Answer:
a)  t = 1.47 h   b) t = 1.32 h
Explanation:
a) Â In this problem the plane and the wind are in the same North-South direction, whereby the vector sum is reduced to the scalar sum (ordinary). Let's calculate the total speed
   v = [tex]v_{f}[/tex]f - [tex]v_{w}[/tex]
   v = 585 -32.1
   v = 552.9 km / h
We use the speed ratio in uniform motion
   v = x / t
   t = x / v
   t = 815 /552.9
   t = 1.47 h
b) Â We repeat the calculation, but this time the wind is going in the direction of the plane
   v=  [tex]v_{f}[/tex]f - [tex]v_{w}[/tex]
   v 585 + 32.1
   v = 617.1 km / h
   t = 815 /617.1
   t = 1.32 h