Answer:
The current value of the stamp collection is of $2,191.
Explanation:
Compound interest:
The compound interest formula is given by:
![A(t) = P(1 + (r)/(n))^(nt)](https://img.qammunity.org/2022/formulas/mathematics/college/jij6dzyugcwh9r2wcu470rclc9mroo9e6g.png)
Where A(t) is the amount of money after t years, P is the principal(the initial sum of money), r is the interest rate(as a decimal value), n is the number of times that interest is compounded per year and t is the time in years for which the money is invested or borrowed.
A stamp collection is purchased for $1,000.
This means that
![P = 1000](https://img.qammunity.org/2022/formulas/mathematics/college/kpicxnslgdblewhnqruuai8c4m4sxrftn2.png)
The rate of return on the stamp collection is 4% per year
This means that
![n = 1, r = 0.04](https://img.qammunity.org/2022/formulas/mathematics/college/u23i4a39ldvu6pa9nufsxokgrybk5zk6g0.png)
So
![A(t) = P(1 + (r)/(n))^(nt)](https://img.qammunity.org/2022/formulas/mathematics/college/jij6dzyugcwh9r2wcu470rclc9mroo9e6g.png)
![A(t) = 1000(1 + 0.04)^(t)](https://img.qammunity.org/2022/formulas/mathematics/college/r07d205lfgvrapishtjml1h7o06rka5k3j.png)
![A(t) = 1000(1.04)^(t)](https://img.qammunity.org/2022/formulas/mathematics/college/oyu4e7xl3crvhmm2jtnziswkchzanwbrkc.png)
What is the current value of the stamp collection?
This is A(20). So
![A(20) = 1000(1.04)^(20) = 2191](https://img.qammunity.org/2022/formulas/mathematics/college/b7hkekkm9emzh3fsq6szjbwxszzjr4oxj7.png)
The current value of the stamp collection is of $2,191.