\documentclass [12pt] {article}

\usepackage{graphicx, xypic,amsmath}

\topmargin 0pt
\advance \topmargin by -\headheight
\advance \topmargin by -\headsep
\textheight 8.9in
\oddsidemargin 0pt
\evensidemargin \oddsidemargin
\marginparwidth 0.5in
\textwidth 6.5in

\begin{document}
\begin{center}

\Huge{
Logarithms \& their uses}
\end{center}


\begin{enumerate}

\item Cholera, an intestinal disease, is caused by a cholera bacterium that multiplies exponentially by cell division as modeled by $A=A_0e^{1.386t}$ where $A$ is the number of bacteria present after $t$ hours and $A_0$ is the umber of bacteria present at time $t=0$.  Assume that we start with 1 bacterium.
\begin{enumerate}
\item How many bacteria are present after 5 hours?
\vspace{1.5in}
\item Find when there are 1,000,000 bacterium.
\vfill
\end{enumerate}


\item An exponential model for data on rubella is given by $A=54988\cdot 0.799^t$ where $A$ is the number of reported cases of rubella and $t$ is years with $t=0$ representing 1970.
\begin{enumerate}
\item Use the model above to predict the number of rubella cases in 2000.
\vspace{1.5in}
\item Find the year when the number of rubella cases reached 200.
\vfill
\end{enumerate}


\newpage
\item The population of zombies is 2 on Wednesday and 5 a day later.

\begin{enumerate}
\item If the population continues to grow exponentially, how many zombies will there be in a week?
\vspace{3in}
\item How long until the population of UW Tacoma is gone? (note: UW Tacoma has about 4000 students)
\end{enumerate}


\end{enumerate}



\end{document}