Math Problem Statement

the first 5 years it earned interest at a rate of 3.30% compounded semi-annually and for the next 6 years it earned interest at a rate of 5.40% compounded semi-annually. a. Calculate the accumulated value of her investment at the end of 11 years.

Solution

To calculate the accumulated value of the investment, we need to break the problem into two periods: the first 5 years with 3.30% interest compounded semi-annually, and the next 6 years with 5.40% interest compounded semi-annually.

The formula to calculate the accumulated value AA for compound interest is:

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

Where:

  • AA is the accumulated value
  • PP is the principal (initial investment)
  • rr is the annual interest rate (decimal form)
  • nn is the number of compounding periods per year (since it's compounded semi-annually, n=2n = 2)
  • tt is the time in years

Let’s calculate in steps.

Step 1: Calculate the accumulated value after the first 5 years

For the first 5 years:

  • r=3.30%=0.033r = 3.30\% = 0.033
  • n=2n = 2 (since it's compounded semi-annually)
  • t=5t = 5 years

The formula becomes: A1=P(1+0.0332)2×5A_1 = P \left( 1 + \frac{0.033}{2} \right)^{2 \times 5} A1=P(1+0.0165)10A_1 = P \left( 1 + 0.0165 \right)^{10} A1=P(1.0165)10A_1 = P (1.0165)^{10}

Step 2: Calculate the accumulated value after the next 6 years with 5.40% interest

After the first 5 years, the new principal is A1A_1, and it earns interest for another 6 years at 5.40% compounded semi-annually.

  • r=5.40%=0.054r = 5.40\% = 0.054
  • n=2n = 2
  • t=6t = 6 years

The formula for the next 6 years becomes: A2=A1(1+0.0542)2×6A_2 = A_1 \left( 1 + \frac{0.054}{2} \right)^{2 \times 6} A2=A1(1+0.027)12A_2 = A_1 \left( 1 + 0.027 \right)^{12} A2=A1(1.027)12A_2 = A_1 (1.027)^{12}

Step 3: Combine both periods

Now, we combine both calculations. The accumulated value at the end of 11 years is:

A=P(1.0165)10(1.027)12A = P (1.0165)^{10} (1.027)^{12}

You will need to plug in the initial investment amount PP to find the final accumulated value.

Let me know if you have a specific principal value, or if you'd like me to proceed further!

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Math Problem Analysis

Mathematical Concepts

Compound Interest
Exponents
Algebra

Formulas

A = P(1 + r/n)^(nt)

Theorems

Compound Interest Theorem

Suitable Grade Level

Grades 9-12