Find a relationship (equation) for the time of flight as a function of the initial speed for the case /theta =30 degrees. In other words, solve the...

Find a relationship (equation) for the time of flight as a function of the initial speed for the case  =30 degrees. In other words, solve the problem: what will be the time of flight of a ball launched under an angle with the horizontal axis of theta=30 degrees, with a velocity V0 ? (The ball is launched from a horizontal surface and will fall on the same surface).

This is a lab question from my projectile motion physics lab. Am I supposed to make an equation from data I collected in lab, or am I only supposed to solve it using the information given in the problem? If the latter is the case I'm stumped since it only tells you the direction (30 degrees). If I am supposed to use collected data I still don't have a good grasp on how to make the equation.