A person jumps off a 20m high cliff into the water below. The height of the person above the ground at t time seconds is given by the equation h=-5t^2+30. How long does it take the person to reach the half way mark to the water?

Answer 1

just solve for height=10:

10 = -5t^2+30

t = 2

Answer 2

Good, correct answer just not sure how you got it. I do but what are the steps