A firecracker is shot upward off a balcony that is 10 feet above the ground with an initial velocity of v feet per second. The firecracker reaches a maximum height of 30.25 feet at 1.125 seconds after being shot upward. The formula for the vertical motion of an object is
where the gravitational constant, a, is -32 feet per second, and h(t) is the height in feet modeled as a function of time, t.

The initial velocity of the firecracker is
A. 12
B. 27
C. 36
feet per second

The time when the firecracker reaches the ground is
A. 1.25
B. 2
C. 2.5
seconds

The correct answers are C and C I just need to understand why.
Thanks!