Homework Help: Math

Posted by Anonymous on Monday, February 11, 2013 at 9:39am.

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?

Math - Steve, Monday, February 11, 2013 at 10:12am
just solve for height=10:

10 = -5t^2+30

t = 2

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