Step-by-step explanation:
In the velocity triangle in the attachment we have
w = velocity of raindrop relative to ground.
v1 = 25 m/s, velocity of the car (going north) relative to ground.
u1 = velocity of raindrop relative to car
w = vector sum of u1 and v1
v2 = 25 m/s, velocity of the car (going south) relative to ground.
u2 = velocity of raindrop relative to car (vertically down)
w = vector sum of u2 and v2
from the figure we can write
= 64.08 m/s
now, we can calculate w as resultant of v2 and u2
w =

w= 68.7 m/s
also, direction of w theta = arctan(v2/u2) = 21.3 °