Toy Gun Optimization
1. **State the problem:**
We want to maximize the weekly profit from producing two toy guns: Acer and Bulls-I.
2. **Define variables:**
Let $x$ = dozens of Bulls-I produced.
Let $y$ = dozens of Acer produced.
3. **Objective function:**
Maximize profit $P = 5x + 8y$ (since Bulls-I yields 5 profit per dozen, Acer yields 8).
4. **Constraints:**
- Plastic: $2y + 1x \leq 1000$ (pounds of plastic)
- Labor: $3y + 4x \leq 2400$ (minutes; 40 hours = 2400 minutes)
- Marketing total: $x + y \leq 700$ (dozens)
- Marketing difference: $y - x \leq 350$
- Non-negativity: $x \geq 0$, $y \geq 0$
5. **Rewrite constraints for clarity:**
- Plastic: $2y + x \leq 1000$
- Labor: $3y + 4x \leq 2400$
- Total production: $x + y \leq 700$
- Difference: $y \leq x + 350$
6. **Graphical interpretation:**
The feasible region is bounded by these inequalities, forming a polygon.
7. **Find intersection points (corner points) of constraints:**
- Intersection of plastic and labor:
Solve system:
$$\begin{cases} 2y + x = 1000 \\ 3y + 4x = 2400 \end{cases}$$
Multiply first by 4:
$$8y + 4x = 4000$$
Subtract second:
$$(8y + 4x) - (3y + 4x) = 4000 - 2400 \Rightarrow 5y = 1600 \Rightarrow y = 320$$
Then $x = 1000 - 2y = 1000 - 640 = 360$
- Intersection of plastic and total production:
$$\begin{cases} 2y + x = 1000 \\ x + y = 700 \end{cases}$$
From second: $x = 700 - y$
Substitute:
$$2y + 700 - y = 1000 \Rightarrow y = 300$$
Then $x = 700 - 300 = 400$
- Intersection of labor and total production:
$$\begin{cases} 3y + 4x = 2400 \\ x + y = 700 \end{cases}$$
From second: $y = 700 - x$
Substitute:
$$3(700 - x) + 4x = 2400 \Rightarrow 2100 - 3x + 4x = 2400 \Rightarrow x = 300$$
Then $y = 700 - 300 = 400$
- Intersection of difference and total production:
$$\begin{cases} y = x + 350 \\ x + y = 700 \end{cases}$$
Substitute first into second:
$$x + (x + 350) = 700 \Rightarrow 2x = 350 \Rightarrow x = 175$$
Then $y = 175 + 350 = 525$
- Check if these points satisfy all constraints and non-negativity.
8. **Evaluate profit at each feasible corner point:**
- At $(x,y) = (360,320)$:
$$P = 5(360) + 8(320) = 1800 + 2560 = 4360$$
- At $(400,300)$:
$$P = 5(400) + 8(300) = 2000 + 2400 = 4400$$
- At $(300,400)$:
$$P = 5(300) + 8(400) = 1500 + 3200 = 4700$$
- At $(175,525)$:
$$P = 5(175) + 8(525) = 875 + 4200 = 5075$$
9. **Check feasibility of $(175,525)$:**
- Plastic: $2(525) + 175 = 1050 + 175 = 1225 > 1000$ (violates plastic constraint)
So $(175,525)$ is not feasible.
10. **Check other points for all constraints:**
- $(300,400)$:
Plastic: $2(400) + 300 = 800 + 300 = 1100 > 1000$ (not feasible)
- $(400,300)$:
Plastic: $2(300) + 400 = 600 + 400 = 1000$ (feasible)
Labor: $3(300) + 4(400) = 900 + 1600 = 2500 > 2400$ (not feasible)
- $(360,320)$:
Plastic: $2(320) + 360 = 640 + 360 = 1000$ (feasible)
Labor: $3(320) + 4(360) = 960 + 1440 = 2400$ (feasible)
Total: $360 + 320 = 680 \leq 700$ (feasible)
Difference: $320 - 360 = -40 \leq 350$ (feasible)
11. **Conclusion:**
The only feasible corner point with maximum profit is $(x,y) = (360,320)$ with profit $P = 4360$.
12. **Compare with current plan:**
Current profit is 4100 at $(100,450)$.
New plan increases profit to 4360.
**Final answer:**
Produce 360 dozens of Bulls-I and 320 dozens of Acer to maximize profit at 4360 per week.