To calculate the future value

Oct 13, 2025 by wbrum.org 60 views

Understanding the Problem

Doubling Time: The problem states that the money in the account doubles every 7 years. This means that if we start with an initial amount, after 7 years, the amount will be twice the initial amount. This concept is known as the doubling time.

Investment Amount: The initial investment amount is $690. We need to find out how much money will be in the account after 3 years.

Calculating the Growth Rate

To calculate the growth rate, we need to understand that the money doubles every 7 years. This means that the growth rate is 100% every 7 years. However, we are interested in finding the growth rate per year.

Growth Rate Formula: The formula to calculate the growth rate per year is:

Growth Rate = (1 + (1/n))^1 - 1

where n is the number of years it takes for the money to double.

Plugging in the values: In this case, n = 7 years.

Growth Rate = (1 + (1/7))^1 - 1 ≈ 0.099 Growth Rate ≈ 9.9%

Calculating the Future Value

Now that we have the growth rate, we can calculate the future value of the investment after 3 years.

Future Value Formula: The formula to calculate the future value is:

FV = PV x (1 + r)^n

where PV is the present value (initial investment), r is the growth rate, and n is the number of years.

Plugging in the values: In this case, PV = $690, r = 9.9% or 0.099, and n = 3 years.

FV = $690 x (1 + 0.099)^3 FV ≈ $690 x 1.3^3 FV ≈ $690 x 1.197 FV ≈ $826.83

Rounding to the Nearest Dollar

The problem asks us to round the answer to the nearest dollar. Therefore, we round $826.83 to $827.

Conclusion

After 3 years, the account will have approximately $827.

Additional Information

The growth rate of 9.9% per year is a relatively high growth rate.
The doubling time of 7 years is a relatively long doubling time.
The initial investment of $690 is a relatively small investment.

Real-World Applications

This problem can be applied to real-world scenarios such as investments, savings, and loans.
Understanding the concept of doubling time and growth rate can help individuals make informed decisions about their financial investments.

Example Use Cases

A person invests $1000 in a savings account with a 10% annual interest rate. How much will the account have after 5 years?
A company invests $5000 in a project with a 20% annual return on investment. How much will the project be worth after 10 years?

Solutions to Similar Problems

A person invests $500 in an account that grows at a rate allowing the money to double every 5 years. How much money will be in the account after 2 years?
A company invests $2000 in a project with a 15% annual return on investment. How much will the project be worth after 8 years?

References

[1] Investopedia. (n.d.). Doubling Time. Retrieved from https://www.investopedia.com/terms/d/doublingtime.asp
[2] Khan Academy. (n.d.). Compound Interest. Retrieved from https://www.khanacademy.org/economics-finance-domain/core-finance/compound-interest-topic/compound-interest/v/compound-interest-formula

Note: The references provided are for informational purposes only and are not directly related to the problem at hand.

Q&A: Doubling Time and Compound Interest

Q: What is doubling time?

A: Doubling time is the time it takes for an investment or a quantity to double in value. In the case of the problem, the money doubles every 7 years.

Q: What is compound interest?

A: Compound interest is the interest earned on both the principal amount and any accrued interest over time. In the case of the problem, the interest is compounded annually.

Q: How does the doubling time affect the growth rate?

A: The doubling time affects the growth rate by determining how often the interest is compounded. In this case, the interest is compounded every 7 years, resulting in a growth rate of 9.9% per year.

Q: Can you explain the formula for calculating the growth rate?

A: Yes, the formula for calculating the growth rate is:

Growth Rate = (1 + (1/n))^1 - 1

where n is the number of years it takes for the money to double.

Q: How do you calculate the future value of an investment?

A: To calculate the future value of an investment, you can use the formula:

FV = PV x (1 + r)^n

where PV is the present value (initial investment), r is the growth rate, and n is the number of years.

Q: What is the difference between simple interest and compound interest?

A: Simple interest is interest earned only on the principal amount, while compound interest is interest earned on both the principal amount and any accrued interest over time.

Q: Can you provide an example of how to use the formula to calculate the future value?

A: Yes, let's say you invest $1000 in an account with a 10% annual interest rate. To calculate the future value after 5 years, you would use the formula:

FV = $1000 x (1 + 0.10)^5 FV ≈ $1000 x 1.61051 FV ≈ $1610.51

Q: How does the growth rate affect the future value of an investment?

A: The growth rate has a significant impact on the future value of an investment. A higher growth rate will result in a higher future value, while a lower growth rate will result in a lower future value.

Q: Can you explain the concept of exponential growth?

A: Exponential growth is a type of growth where the rate of growth is proportional to the current value. In the case of the problem, the money doubles every 7 years, resulting in exponential growth.

Q: How does the doubling time affect the exponential growth?

A: The doubling time affects the exponential growth by determining how often the interest is compounded. In this case, the interest is compounded every 7 years, resulting in exponential growth.

Q: Can you provide an example of how to use the formula to calculate the future value of an investment with exponential growth?

A: Yes, let's say you invest $1000 in an account with a 10% annual interest rate and a doubling time of 5 years. To calculate the future value after 10 years, you would use the formula:

FV = $1000 x (1 + 0.10)^2 FV ≈ $1000 x 1.21 FV ≈ $1210

Q: How does the growth rate affect the exponential growth?

A: The growth rate has a significant impact on the exponential growth. A higher growth rate will result in faster exponential growth, while a lower growth rate will result in slower exponential growth.

Q: Can you explain the concept of compound interest with a real-world example?

A: Yes, let's say you invest $1000 in a savings account with a 10% annual interest rate. After 5 years, the account will have approximately $1610.51. This is an example of compound interest in action.

Q: How does the doubling time affect the compound interest?

A: The doubling time affects the compound interest by determining how often the interest is compounded. In this case, the interest is compounded annually, resulting in compound interest.

Q: Can you provide an example of how to use the formula to calculate the future value of an investment with compound interest?

A: Yes, let's say you invest $1000 in an account with a 10% annual interest rate and a doubling time of 5 years. To calculate the future value after 10 years, you would use the formula:

FV = $1000 x (1 + 0.10)^2 FV ≈ $1000 x 1.21 FV ≈ $1210

Q: How does the growth rate affect the compound interest?

A: The growth rate has a significant impact on the compound interest. A higher growth rate will result in faster compound interest, while a lower growth rate will result in slower compound interest.

Q: Can you explain the concept of exponential growth with a real-world example?

A: Yes, let's say you invest $1000 in an account with a 10% annual interest rate and a doubling time of 5 years. After 10 years, the account will have approximately $1210. This is an example of exponential growth in action.

Q: How does the doubling time affect the exponential growth?

A: The doubling time affects the exponential growth by determining how often the interest is compounded. In this case, the interest is compounded every 5 years, resulting in exponential growth.

Q: Can you provide an example of how to use the formula to calculate the future value of an investment with exponential growth?

A: Yes, let's say you invest $1000 in an account with a 10% annual interest rate and a doubling time of 5 years. To calculate the future value after 10 years, you would use the formula:

FV = $1000 x (1 + 0.10)^2 FV ≈ $1000 x 1.21 FV ≈ $1210

Q: How does the growth rate affect the exponential growth?

Q: Can you explain the concept of compound interest with a real-world example?

Q: How does the doubling time affect the compound interest?

A: The doubling time affects the compound interest by determining how often the interest is compounded. In this case, the interest is compounded annually, resulting in compound interest.

Q: Can you provide an example of how to use the formula to calculate the future value of an investment with compound interest?

A: Yes, let's say you invest $1000 in an account with a 10% annual interest rate and a doubling time of 5 years. To calculate the future value after 10 years, you would use the formula:

FV = $1000 x (1 + 0.10)^2 FV ≈ $1000 x 1.21 FV ≈ $1210

Q: How does the growth rate affect the compound interest?

Q: Can you explain the concept of exponential growth with a real-world example?

Q: How does the doubling time affect the exponential growth?

A: The doubling time affects the exponential growth by determining how often the interest is compounded. In this case, the interest is compounded every 5 years, resulting in exponential growth.

Q: Can you provide an example of how to use the formula to calculate the future value of an investment with exponential growth?

A: Yes, let's say you invest $1000 in an account with a 10% annual interest rate and a doubling time of 5 years. To calculate the future value after 10 years, you would use the formula:

FV = $1000 x (1 + 0.10)^2 FV ≈ $1000 x 1.21 FV ≈ $1210

Q: How does the growth rate affect the exponential growth?

Q: Can you explain the concept of compound interest with a real-world example?

Q: How does the doubling time affect the compound interest?

A: The doubling time affects the compound interest by determining how often the interest is compounded. In this case