## Problema Solution

Before a football game, a coin toss is used to determine which team will kick off. The height h (in feet) of a coin above the t seconds after being flipped up into the air is given by h=-16t^2+22t +3. How long does the team captain have to call heads or tails if it must be done while the coin is in the air?

## Answer provided by our tutors

He has until it hits the ground, at h(t) = 0

or, -16t^2 + 22t + 20 = 0

Factor out a 2 from each coefficient to get:

-8t^2 + 11t + 10 = 0

Factors for this equation should be:

(8t + 5) * (-t + 2)= 0

You get:

-t = -2 which becomes t = 2

or you get:

8t = -5 which you reject right away because it's negative, and t can't be negative.

Your answer should be t = 2

This means that he gets 2 seconds to call heads or tails before the coin hits the ground.