Math Problem Statement

How much money should be deposited today in an account that earns 4.5 % compounded monthly so that it will accumulate to $ 11,000 in 4 ​years?

Solution

To determine how much money should be deposited today to accumulate $11,000 in 4 years with an interest rate of 4.5% compounded monthly, we can use the formula for compound interest:

A=P(1+rn)ntA = P \left(1 + \frac{r}{n}\right)^{nt}

Where:

  • AA is the future value (what we want to accumulate, $11,000).
  • PP is the present value (the initial deposit, which we're solving for).
  • rr is the annual interest rate (4.5%, or 0.045).
  • nn is the number of times the interest is compounded per year (monthly compounding means n=12n = 12).
  • tt is the time in years (4 years).

We need to solve for PP. Rearranging the formula to solve for PP:

P=A(1+rn)ntP = \frac{A}{\left(1 + \frac{r}{n}\right)^{nt}}

Now, plugging in the values:

P=11,000(1+0.04512)12×4P = \frac{11,000}{\left(1 + \frac{0.045}{12}\right)^{12 \times 4}}

Let's calculate this:

P=11,000(1+0.00375)48P = \frac{11,000}{\left(1 + 0.00375\right)^{48}}

P=11,000(1.00375)48P = \frac{11,000}{\left(1.00375\right)^{48}}

P=11,0001.197992P = \frac{11,000}{1.197992}

P9,181.49P \approx 9,181.49

So, you would need to deposit approximately $9,181.49 today to accumulate $11,000 in 4 years at an interest rate of 4.5%, compounded monthly.

Do you want more details or have any questions about this?

Here are 5 related questions:

  1. How would the answer change if the interest were compounded annually instead of monthly?
  2. What happens to the required initial deposit if the interest rate increases to 5%?
  3. How would the formula adjust for a quarterly compounding period?
  4. How much interest would be earned after 4 years on the initial deposit?
  5. What if the investment goal was $15,000 instead of $11,000?

Tip: When dealing with compound interest, the more frequently the interest is compounded, the greater the accumulated amount will be.