Maximize Profit 983394
1. **State the problem:**
We want to maximize the profit from manufacturing chairs, tables, and bookcases given constraints on cutting, assembly, and finishing hours.
2. **Define variables:**
Let $x$ = number of chairs, $y$ = number of tables, $z$ = number of bookcases.
3. **Write the objective function:**
Maximize profit:
$$P = 20x + 30y + 25z$$
4. **Write the constraints based on operation hours:**
Cutting: $$1x + 1y + 3z \leq 600$$
Assembly: $$1x + 2y + 1z \leq 500$$
Finishing: $$1x + 1y + 1z \leq 300$$
5. **Non-negativity constraints:**
$$x, y, z \geq 0$$
6. **Convert inequalities to equalities by adding slack variables:**
$$x + y + 3z + s_1 = 600$$
$$x + 2y + z + s_2 = 500$$
$$x + y + z + s_3 = 300$$
where $s_1, s_2, s_3 \geq 0$ are slack variables.
7. **Set up the initial simplex tableau:**
| Basis | $x$ | $y$ | $z$ | $s_1$ | $s_2$ | $s_3$ | RHS |
|-------|-----|-----|-----|-------|-------|-------|-----|
| $s_1$ | 1 | 1 | 3 | 1 | 0 | 0 | 600 |
| $s_2$ | 1 | 2 | 1 | 0 | 1 | 0 | 500 |
| $s_3$ | 1 | 1 | 1 | 0 | 0 | 1 | 300 |
| $P$ | -20 | -30 | -25 | 0 | 0 | 0 | 0 |
8. **Perform simplex iterations:**
- Identify entering variable: most negative coefficient in $P$ row is $-30$ for $y$.
- Identify leaving variable by minimum ratio test:
- $s_1$: $600/1=600$
- $s_2$: $500/2=250$
- $s_3$: $300/1=300$
So $s_2$ leaves.
9. **Pivot on $y$ in $s_2$ row:**
Divide $s_2$ row by 2:
$$[0.5, 1, 0.5, 0, 0.5, 0, 250]$$
10. **Update other rows to zero out $y$ column:**
- $s_1$ new = $s_1$ - $1 \times s_2$ row
- $s_3$ new = $s_3$ - $1 \times s_2$ row
- $P$ new = $P$ + $30 \times s_2$ row
After calculations:
$s_1$: $[1 - 0.5, 1 - 1, 3 - 0.5, 1 - 0, 0 - 0.5, 0 - 0, 600 - 250] = [0.5, 0, 2.5, 1, -0.5, 0, 350]$
$s_3$: $[1 - 0.5, 1 - 1, 1 - 0.5, 0 - 0, 0 - 0.5, 1 - 0, 300 - 250] = [0.5, 0, 0.5, 0, -0.5, 1, 50]$
$P$: $[-20 + 30*0.5, -30 + 30*1, -25 + 30*0.5, 0 + 30*0, 0 + 30*0.5, 0 + 30*0, 0 + 30*250] = [-5, 0, -10, 0, 15, 0, 7500]$
11. **Next iteration:**
Entering variable: most negative in $P$ row is $-10$ for $z$.
Leaving variable by ratio test:
- $s_1$: $350/2.5=140$
- $s_3$: $50/0.5=100$
$s_3$ leaves.
12. **Pivot on $z$ in $s_3$ row:**
Divide $s_3$ row by 0.5:
$$[1, 0, 1, 0, -1, 2, 100]$$
13. **Update other rows:**
$s_1$ new = $s_1$ - $2.5 \times s_3$ row
$P$ new = $P$ + $10 \times s_3$ row
$s_1$: $[0.5 - 2.5*1, 0 - 2.5*0, 2.5 - 2.5*1, 1 - 2.5*0, -0.5 - 2.5*(-1), 0 - 2.5*2, 350 - 2.5*100] = [-2, 0, 0, 1, 2, -5, 100]$
$P$: $[-5 + 10*1, 0 + 10*0, -10 + 10*1, 0 + 10*0, 15 + 10*(-1), 0 + 10*2, 7500 + 10*100] = [5, 0, 0, 0, 5, 20, 8500]$
14. **Check optimality:**
All coefficients in $P$ row for variables $x,y,z$ are non-negative, so optimal solution reached.
15. **Read solution:**
Basic variables: $y$ and $z$ from previous pivots, and $s_1$.
From $s_3$ row: $z = 100$
From $s_2$ row (now $y$ row): $y = 250$
From $s_1$ row: $x = 0$ (since $x$ is non-basic)
16. **Interpretation:**
Produce 0 chairs, 250 tables, and 100 bookcases to maximize profit.
17. **Maximum profit:**
$$P = 20(0) + 30(250) + 25(100) = 0 + 7500 + 2500 = 10000$$
**Final answer:**
Produce 0 chairs, 250 tables, and 100 bookcases for a maximum profit of 10000.