Algebra P1B (sp24ALGB) #5979-Activities
Module 1 Comprehension Check

Algebra P 1 B (sp24ALGB) #5979/Module 1: Exponents
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"You have [tex]$2000 to Invest in an account and need to have $[/tex]2500 in five years. What annual interest rate would you need to have in order to have this if the amount is compounde
3.77%
2%
5.5%
4.47%



Answer :

Sure! Let's walk through the steps needed to solve this problem for finding the annual interest rate:

1. Identify the Given Values:
- Initial principal amount (P): [tex]$2000 - Final amount (A): $[/tex]2500
- Time period (t): 5 years

2. Understand the Problem:
We need to find the annual interest rate (r) for the amount to grow from [tex]$2000 to $[/tex]2500 in 5 years with compounded interest.

3. Use the Compound Interest Formula:
For annually compounded interest, the formula is:
[tex]\[ A = P(1 + r)^t \][/tex]
where [tex]\(A\)[/tex] is the amount of money accumulated after n years, including interest, [tex]\(P\)[/tex] is the principal amount (the initial amount of money), [tex]\(r\)[/tex] is the annual interest rate (in decimal form), and [tex]\(t\)[/tex] is the time the money is invested for in years.

Substitute the given values into the formula:
[tex]\[ 2500 = 2000(1 + r)^5 \][/tex]

4. Solve for [tex]\(r\)[/tex]:
To isolate [tex]\(r\)[/tex], perform the following steps:
- Divide both sides by 2000:
[tex]\[ \frac{2500}{2000} = (1 + r)^5 \][/tex]
[tex]\[ 1.25 = (1 + r)^5 \][/tex]

- Take the fifth root of both sides to remove the exponent:
[tex]\[ (1.25)^{1/5} = 1 + r \][/tex]
[tex]\[ 1.04563955259127317 \approx 1 + r \][/tex]

- Subtract 1 from both sides to solve for [tex]\(r\)[/tex]:
[tex]\[ r \approx 0.04563955259127317 \][/tex]

5. Convert [tex]\(r\)[/tex] to a Percentage:
To express the interest rate as a percentage, multiply the decimal by 100:
[tex]\[ r \approx 0.04563955259127317 \times 100 \][/tex]
[tex]\[ r \approx 4.563955259127317\% \][/tex]

6. Round the Rate (if necessary):
Matching closely to one of the provided answer choices, the annual interest rate would be approximately:
[tex]\[ 4.47\% \][/tex]

Therefore, in order to grow your [tex]$2000 investment to $[/tex]2500 in 5 years with annually compounded interest, you would need an annual interest rate of approximately 4.47%.