Height of toss

-h = vo sinθ t - 1/2 g t^2...(1) vo cosθ t = 24. put t = 2s vo cosθ = 12 m = v' v'^2 - (vo sinθ)^2= 2 10 h.......(2) 144 - (vo sinθ)^2 = 20 h. From the above equation you can see that h cannot be 8. Now try 4. We get vo*sinθ = 16. It satisfies the equation(1)

h = -vo.sin(theta).t +g.t²/2 [1]

theta2 = 45, then:

v.sin(theta2) = v.cos(theta2)

-vo.sin(theta) + g.t = vo.cos(theta) [2]

vo.cos(theta).t = d

vo.cos(theta) = d/t [3]

[1]+[2]+[3]:

h = (d/t - g.t).t + g.t²/2 = d - gt²/2

h = 24 - 10.2²/2 = 4m

Not a solution but can you edit the question to specify gravity as $g=10m{ s }^{ -2 }$ cause I took $g=9.81m{ s }^{ -2 }$ and got 4.38m