33.33%
Do 206/618 which is 0.3333333..
Move the decimal two places to the right.
30 because 0.3 * 100 = 30
The function in vertex form is

(refer to your other post I solved it there).
The general form of quadratic equations in vertex form is

, where (h, k) is the vertex of the parabola.
Here, a = 1, h = -6 and k = -54
Therefore, the vertex is (-6, -54) and it is a maximum because a = 1 is postive.