Answer
$f(t(p)) =3 e^{4 p^{2}}$ and $f(t(2)) =3 e^{16}$
Work Step by Step
Given $$
f(t)=3 e^{t} ; t(p)=4 p^{2}
$$
Since $f(t(p))$ is given by
\begin{align*}
f(t(p))&=3 e^{p(t)} \\
&=3 e^{4 p^{2}}
\end{align*}
and $f(t(2)) =3 e^{16}$