Write the formula for centripetal acceleration.
From that, determine the tangential velocity, which when the ball leaves the tube, is horizontal, i.e. in +x-direction, so that gives vx.
Assuming no air resistance, what can one assume about the horizontal velocity?
Now as soon as the ball leaves the tube, it starts to fall, so there is a downward vy which increases downward with acceleration of gravity. From this one can determine the time that the ball air airborne.
Know vx and t in air, one can determine the distance traveled.