Math Problem Statement

You win $12,000 in the lottery. You decide to deposit the money in a savings account until you graduate from college in 7 years. Your bank can give you an interest rate of 7.5% compounded continuously. How much will you have in your account after 7 years? Round your answer to the nearest cent.

Solution

The problem describes a scenario where you deposit $12,000 in a savings account that offers 7.5% interest compounded continuously for 7 years. We are tasked with finding how much will be in the account after 7 years, rounding to the nearest cent.

To solve this, we use the formula for continuous compounding:

A=PertA = P \cdot e^{rt}

Where:

  • AA is the amount of money after time tt,
  • PP is the principal amount (initial deposit),
  • rr is the annual interest rate (in decimal),
  • tt is the time in years,
  • ee is Euler's number (approximately 2.71828).

Given values:

  • P=12,000P = 12,000
  • r=7.5%=0.075r = 7.5\% = 0.075
  • t=7t = 7 years

Substituting these into the formula:

A=12,000e0.075×7A = 12,000 \cdot e^{0.075 \times 7}

Let's calculate this step-by-step.

  1. Multiply the interest rate and time: 0.075×7=0.5250.075 \times 7 = 0.525

  2. Find e0.525e^{0.525}: e0.5251.69046e^{0.525} \approx 1.69046

  3. Now multiply this by the principal: A=12,0001.6904620,285.52A = 12,000 \cdot 1.69046 \approx 20,285.52

Thus, after 7 years, the amount in your account will be $20,285.52.

Would you like more details on this calculation or have any questions?

Here are 5 follow-up questions:

  1. How would the final amount change if the interest rate were 8%?
  2. What would be the amount after 10 years instead of 7?
  3. How is continuous compounding different from yearly compounding?
  4. What if you deposited $15,000 instead of $12,000?
  5. Can you compare continuous compounding with monthly compounding for this case?

Tip: Continuous compounding grows money faster than other types of compounding because it assumes the interest is added at every possible moment.

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Math Problem Analysis

Mathematical Concepts

Continuous Compounding
Exponential Growth

Formulas

A = P * e^(rt)

Theorems

Euler's number and continuous compounding

Suitable Grade Level

Grades 9-12