The staging platform for a fireworks display is $6 \mathrm{ft}$ above ground, and the mortars leave the platform at $96 \mathrm{ft} / \mathrm{sec}$. The height of the mortars $h(t)$ (in feet) can be modeled by $h(t)=-16(t-3)^{2}+150,$ where $t$ is the time in seconds after launch.
a. If the fuses are set for 3 sec after launch, at what height will the fireworks explode?
b. Will the fireworks explode at their maximum height? Explain.