# Question #288b9

##### 1 Answer

4 seconds.

#### Explanation:

Damn, this kid has got some seriously strong legs.

graph{-16x^2+64x [-72.2, 75.9, -4, 70]}

Comment aside, I think we should rewrite the function to best suit the current circumstance:

Now, we have a function of time. This graph above shows the relationship between the ball's height

Alright, so all we need to do is to find the difference in time. The difference in time, let's call it

And the x-intercepts can be found using the quadratic formula:

With