What Is the Initial Speed of a Ball Thrown at an Angle to Return in 3 Seconds?

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Homework Statement

A ball thrown straight upward returns to its original level in 3.00 s. A second ball is thrown at an angle of 36.0° above the horizontal. What is the initial speed of the second ball if it also returns to its original level in 3.00 s?
anwer : ___ m/s

Homework Equations

i need help finding the correct equation which would guide me to a correct answer

The Attempt at a Solution

 

[R.Harmon]

Consider the vertical motion of the particle. You know that v=u+at. Take the final velocity v to be zero (at the maximum height of the particle, and halfway through the motion). You know the time t (half of the total time), and the acceleration due to gravity. This let's you find the initial vertical velocity of the particle, which you can then resolve to find the initial speed. Hope that makes sense and helps!