Math Problem Statement

Luther opened a savings account and deposited $400.00 as principal. The account earns 5% interest, compounded annually. What is the balance after 2 years? Use the formula A=P1+ r

n nt, where A is the balance (final amount), P is the principal (starting amount), r is the interest rate expressed as a decimal, n is the number of times per year that the interest is compounded, and t is the time in years. Round your answer to the nearest cent.

Solution

The formula to calculate the final balance in the account is:

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

Where:

  • AA is the final amount (balance),
  • PP is the principal (initial deposit),
  • rr is the annual interest rate (in decimal form),
  • nn is the number of times per year the interest is compounded,
  • tt is the time in years.

Given:

  • P=400.00P = 400.00,
  • r=0.05r = 0.05 (5% expressed as a decimal),
  • n=1n = 1 (compounded annually),
  • t=2t = 2 years.

Substitute the values into the formula:

A=400(1+0.051)12A = 400 \left(1 + \frac{0.05}{1}\right)^{1 \cdot 2}

Simplify:

A=400(1+0.05)2A = 400 \left(1 + 0.05\right)^2

A=400(1.05)2A = 400 \left(1.05\right)^2

A=4001.1025A = 400 \cdot 1.1025

A=440.99A = 440.99

Final Answer:

The balance after 2 years is $440.99.

Would you like me to provide more details or clarify any part? 😊


Here are 5 related questions to explore:

  1. How would the balance change if the interest were compounded semi-annually?
  2. What is the interest earned after 2 years in this scenario?
  3. How does the formula work for a different principal amount, say $500?
  4. How much time would it take for the balance to double at the same interest rate?
  5. What happens to the balance if the annual interest rate is increased to 6%?

Tip: Always double-check if the interest is compounded annually, semi-annually, or quarterly; this greatly affects the result.

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Math Problem Analysis

Mathematical Concepts

Compound Interest
Exponential Growth

Formulas

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

Theorems

Compound Interest Formula

Suitable Grade Level

Grades 8-10