How to to find time of flight

A balloon is moving horizontally with a constant velocity of 100 m/s at an altitude of 900 m. The directions to the right and upward have been chosen as positive directions. The balloon releases a box that falls to the ground along a curved trajectory. Ignoring air resistance,

a) Determine the time required for the package to hit the ground.

b) How far will the box travel from the release point before landing on the ground?

c) Find the magnitude of the velocity and the directional angle of the final velocity vector that the box has just before it strikes the ground.