if the diameter of the cylinder is 10, then its radius is half that, or 5, thus
[tex]\bf \textit{total surface area of a cylinder}\\\\
SA=2\pi r(h+r)~~
\begin{cases}
r=radius\\
h=height\\
-----\\
r=5\\
h=3
\end{cases}\implies SA=2\pi (5)(3+5)
\\\\\\
SA=10\pi (8)\implies SA=80\pi[/tex]
