Math Problem Statement

A car was valued at $29,000 in the year 1993. The value depreciated to $10,000 by the year 2004.

A) What was the annual rate of change between 1993 and 2004?

Round the rate of decrease to 4 decimal places.

B) What is the correct answer to part A written in percentage form?

%.

Solution

To solve this problem, we will use the formula for exponential decay, since the car's value is decreasing over time. The formula for exponential decay is:

V(t)=V0×(1r)tV(t) = V_0 \times (1 - r)^t

Where:

  • V(t)V(t) is the value at time tt,
  • V0V_0 is the initial value,
  • rr is the rate of decay per year,
  • tt is the number of years.

Given:

  • Initial value V0=29,000V_0 = 29,000,
  • Final value V(t)=10,000V(t) = 10,000,
  • Time span t=20041993=11t = 2004 - 1993 = 11 years.

We need to find the annual rate of depreciation rr.

Step 1: Set up the equation

10,000=29,000×(1r)1110,000 = 29,000 \times (1 - r)^{11}

Step 2: Solve for 1r1 - r

First, divide both sides of the equation by 29,000:

10,00029,000=(1r)11\frac{10,000}{29,000} = (1 - r)^{11}

1029(1r)11\frac{10}{29} \approx (1 - r)^{11}

Now, take the 11th root of both sides:

(1r)=(1029)111(1 - r) = \left( \frac{10}{29} \right)^{\frac{1}{11}}

Using a calculator:

(1r)0.8017(1 - r) \approx 0.8017

Step 3: Solve for rr

r=10.8017r = 1 - 0.8017

r0.1983r \approx 0.1983

So, the annual rate of depreciation is approximately 0.1983 (to four decimal places).

Part B: Convert the rate into percentage form

To express this rate as a percentage, multiply by 100:

r×10019.83%r \times 100 \approx 19.83\%

Final Answers:

  • A) The annual rate of change is 0.1983.
  • B) The rate of decrease in percentage form is 19.83%.

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


Here are 5 related questions:

  1. What happens to the value of the car if the rate of depreciation decreases?
  2. How would the formula change if the car's value increases over time?
  3. Can the rate of depreciation be constant for all assets over time?
  4. What is the value of the car after 15 years at the same depreciation rate?
  5. How would the problem change if the car's value was given after 20 years instead of 11?

Tip: When dealing with percentage changes, always remember to multiply the decimal rate by 100 to express it as a percentage.

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Math Problem Analysis

Mathematical Concepts

Exponential Decay
Depreciation
Algebra

Formulas

V(t) = V_0 * (1 - r)^t

Theorems

Exponential Decay Formula

Suitable Grade Level

Grades 10-12