Difficulty over a problem relating to the motion of a projectile

How can I solve this problem below. This problem was taken from the curvilinear motion of particles inside the kinematics of particles section. So, for my understanding of this theory, can you solve this problem with respect to the formulae of these sections please.
Note: Neglect the air resistance of this problem.

The asking problem:
A player throws a ball with an initial velocity Vo of 15 m/s from a point A located 1.5 m above the floor. Knowing that the ceiling of the gymnasium is 6 m high, determine the highest point B at which the ball can strike the wall 18 m away.

I let with this problem the drawing relating to it.

The answer of this problem for your verification is:
4.34 m