Chapter 5, Problem 4RP

a.

Explanation of Solution

Optimum solution

“Yes”, Zales still purchase rubies.

Reason

• Let $\text{X1}$ be the Type 1 rings produced and $X2$ be the Type 2 rings produced and $\text{R}$ be the number of rubies purchased.
• The new optimum solution value or profit is calculated by the given formula:

  $\text{New value = Old value – }(\text{Key column value × Key}$

b.

Explanation of Solution

Profit

.

Reason

• Let $\text{X1}$ be the Type 1 rings produced and $X2$ be the Type 2 rings produced and $\text{R}$ be the number of rubies purchased.
• The new optimum solution value or profit is calculated by the given formula:

c.

Explanation of Solution

Pay for another hour of labour

• Let $\text{X1}$ be the Type 1 rings produced and $X2$ be the Type 2 rings produced and

d.

Explanation of Solution

Pay for another sapphire

• Let $\text{X1}$ be the Type 1 rings produced and $X2$ be the Type 2 rings produced and $\text{R}$ be the number of rubies purchased