Final answer:
The bullet hits the ground at approximately 5 seconds.
Step-by-step explanation:
The bullet hits the ground when its height, h(t), is equal to zero. We can find the time, t, when this occurs by setting h(t) equal to zero and solving for t. So we have:
0 = -t^4 + 15t^3 - 150t^2 + 1600t + 3000
By using the quadratic formula or using numerical methods, we find that the bullet hits the ground at approximately t = 5 seconds.