Exhibit 81
the Following Questions Pertain to the Problem and Spreadsheet

Exhibit 8.1
The following questions pertain to the problem and spreadsheet below.
A company makes products A and B from 2 resources,labor and material.The company wants to determine the selling price which will maximize profits.A unit of A costs 25 to make and demand is estimated to be 20 ? .10 * Price of A.A unit of B costs 18 to make and demand is estimated to be 30 ? .07 * Price of B.The utilization of labor and materials and the available quantity of resources is shown in the table.A reasonable price for the products is between 100 and 200.
$\begin{array}{lccc}\text { Product } & \text { A } & \text { B } & \text { Avalable resources } \\\hline \text { Labor hr/unit) } & 3 & 2 & 150 \\\text { Material ounces/unit) } & 1 & 2 & 200 \\\text { Manufacturing cost\$/unit) } & 25 & 18 & \\\text { Demand units) } & 20-.10^{*} \mathrm{P}_{1} & 30-.07^{*} \mathrm{P}_{2} &\end{array}$
Let X₁ = demand for As and X₂ = demand for Bs.Let P₁ = price for As and P₂ = price for Bs

-An investor wants to determine how much interest he must earn to be able to make the payments on a 10-year mortgage which has increasing annual payments.The problem is summarized in the accompanying spreadsheet.The investor has enough money to make an initial investment of $9,000 and hopes he can earn 12%,compounded quarterly,on his investments.He would like to know how low his annual return can be and still allow him to make his payments from interest income.What formula goes in cell C7 of the spreadsheet?

A) $\left.=\mathrm{B} 7^{*} 1+\$ \mathrm{C} \$ 3 / 4\right) ^{\wedge} 4-\mathrm{B} 7$
B) $\left.=\mathrm{B} 7^{*} 1+\$ \mathrm{C} \$ 3\right) -\mathrm{B} 7$

C) $\left.=\mathrm{B} 7^{*} \$ \mathrm{C} \$ 3 / 4\right) ^{\wedge} 4-\mathrm{B} 7$
D) $\left.=\mathrm{B} 7^{*} 1+\$ \mathrm{C} \$ 3 / 4\right) ^{\wedge} 4$