RE: Math mini-contest problem for Day 15 on D.Buzz 😎

The answer is 24.805 seconds. I accidently wrote the distance instead of time but deleted the comment. So if you don't count my answer, I understand. I did more work than I needed to.

g=-9.8 m/s (gravity)
s = 15 m/s (speed)

3000= -g/2(t^2) - s(t) = -4.9t^2 + 15 --> Solve for t and you get t=15(sqrt(134)/7))=24.805 seconds.