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Frist, you want to calculate the initial vertical velocity given the angle and initial velocity.
Since the vertical and horizontal motions of projhectile motion should be consider seperately, you can only focus on the vertical aspect of this question and ignore the horizontal motion altogether.
Once you solve that, you can use this equation.
v final = (v initial)+at
For the vertical motion, a is always -9.8m/s^2 which is the acceleration due to gravity.
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For these sorts of questions, it helps to list down quickly the information you know and the information you need to find out so you can determine which formula provides for what you have to find what you need.
Once you get the time to go up, you multiply the time by 2 since the time to go up is teh same as the time to go back down assuming they start and end at teh same height.
Alternatively, you can use the formula T = 2 * (initial ertical speed) / g
This latter formula is a variation on the first one.