\documentclass[12pt,fleqn]{article}
\pagestyle{empty}
\setlength{\topmargin}{-1in}
\setlength{\oddsidemargin}{-.3in}
\setlength{\textheight}{9in}
\setlength{\textwidth}{7.2in}


\begin{document}

\begin{center}
{\Large TEST 2

Math 1090 - 4}
\end{center}
\vspace{.1in}
You have 50 minutes to complete the test.
Show all relevant work (or else no credit).  
Make your work legible, if I can't read it, I can't grade it.  
Each problem is worth 10 points.
\vspace{.1in}

Name \rule{5in}{.2pt}

\vspace{.2in}


\begin{enumerate}

\item  Suppose that an appliance store has found that the demand for 
washing machines is 100 if the price is \$350.
They have also found that the demand is 150 when the price is \$310.
Assuming the demand function is linear, find the equation for demand 
(using $p$ for price and $q$ for quantity.)

\item  The supply and demand functions for a product are given below.
Find the equilibrium point.
\begin{eqnarray*}
\mbox{Demand: } & p = 480-3q \\
\mbox{Supply: } & p = 17q+80
\end{eqnarray*}

\item  Suppose you are working at Gray Whale and sell a bunch of cd's.
You sell some cd's at \$8 each and some at \$9 each.
You end up selling 87 cd's and getting \$732.
How many cd's do you sell at \$8 and how many at \$9?
(You will \underline{not} get credit without setting up the equations.)

\item  You are selling belts for \$12 a belt.
Every month your fixed costs are \$1600 and the belts cost you \$8 per belt.
\begin{enumerate}
\item  Find the cost, revenue and profit functions.
\item  Find the break-even point.
\end{enumerate}

\item  For the matrices below, find the following.
\[
A=\left[
\begin{array}{rrrr}
1 & 2 & 5 & -1 \\
-4 & -3 & 23 & 0 
\end{array}
\right]
\hspace{1in}
B=\left[
\begin{array}{rr}
-7 & -1  \\
0 & 3 \\
1 & -12 \\
6 & 0
\end{array}
\right]
\]
\begin{enumerate}
\item  Order of $A$.
\vspace{.5in}
\item  Order of $B$.
\vspace{.5in}
\item  $A+B$
\end{enumerate}




\end{enumerate}


\end{document}







