Portfolio Allocation
1. **State the problem:**
An investor wants to invest in two companies, Company 1 (extractive) and Company 2 (tech).
2. **Given data:**
- Company 1 price per share: $40
- Company 2 price per share: $25
- Expected Company 1 price after investment: $55
- Expected Company 2 price after investment: $43
- Total investment maximum: $50,000
- Minimum investment in Company 1: $15,000
- Minimum investment in Company 2: $10,000
- Maximum investment in Company 2 due to risk: $25,000
3. **Variables:**
Let $x$ = amount invested in Company 1
Let $y$ = amount invested in Company 2
4. **Constraints:**
$$x + y \leq 50000$$
$$x \geq 15000$$
$$10,000 \leq y \leq 25000$$
5. **Objective:**
Calculate the total number of shares bought in each company:
$$\text{Shares in Company 1} = \frac{x}{40}$$
$$\text{Shares in Company 2} = \frac{y}{25}$$
6. **Expected value after price increase:**
$$\text{Value from Company 1 after increase} = \frac{x}{40} \times 55 = \frac{55x}{40} = 1.375x$$
$$\text{Value from Company 2 after increase} = \frac{y}{25} \times 43 = \frac{43y}{25} = 1.72y$$
7. **Total expected value after investment:**
$$V = 1.375x + 1.72y$$
8. **Optimization problem:**
Maximize $$V = 1.375x + 1.72y$$ with constraints above.
9. **Check corner points:**
- At $x=15000$, $y=10000$,
$$V=1.375(15000)+1.72(10000)=20625+17200=37825$$
- At $x=15000$, $y=25000$,
$$V=1.375(15000)+1.72(25000)=20625+43000=63625$$
- At $x=25000$, $y=25000$ (max $y$ and max $x$ to not exceed $50,000$),
$$V=1.375(25000)+1.72(25000)=34375+43000=77375$$
- At $x=40000$, $y=10000$ (max $x$ given minimum $y$),
$$V=1.375(40000)+1.72(10000)=55000+17200=72200$$
10. **Conclusion:**
The maximum expected value occurs at $x=25000$, $y=25000$.
The investor should invest $25,000 in Company 1 and $25,000 in Company 2 to maximize expected returns under given constraints.