A basketball player, standing near the basket to grab a rebound, jumps 73.6 cm vertically. How much time does the player spend in the bottom 15.4 cm of the jump?

I think I have this right, but I'd like someone to make sure.
First I have to find the total time by plugging 73.6 cm (after converting to m) into the equation "x = vt+1/2at^2." Then I have to subtract 15.4 from 73.6 (which is 58.2 cm), and plug that into the same equation.

Finally I subtract the second time from the total time, and that's my answer.

Correct? Yes? No?

2 answers

No. Using 58.2 cm gives you the time to reach that height. (You will need to use two equations, since V is an unknown also). Subtracting that time from the time it takes to reach 73.6 cm tells you how long you spend in the TOP 15.4 cm of the jump.

Use the height of the jump to solve for V. Then use that V in the equation
x = Vt -(1/2)gt^2 = 0.154 m
to solve for t.
How can I solve for V if I don't yet have the time?