On a banked race track, the smallest circular path on which cars can move has a radius

Question:

On a banked race track, the smallest circular path on which cars can move has a radius of 112 m, while the largest has a radius of 165 m, as the drawing illustrates. The height of the outer wall is 18 m. Find
(a) The smallest and
(b) The largest speed at which cars can move on this track without relying on friction.