aria buys a new car for $36,000 she learns that every year her car will depreciate in value by 15% this means that each year her car will be worth 85% of what is was the previous year. aria tracks how much her car is worth over time.

explain how the amount of money aria's car is worth over time is an example of exponential decay.

it is an example of exponential decay because aria's car is ___ each year by factor of ___

create a sequence that describes the worth of aria's car each year for 8 years (write answers in the format of 2,000 or 1,456.78)

create a formula for the worth of aria's car over time.
y=a*b^x
a= initial amount
b= growth factor

y=___(__)^x

use your formula and find how much aria's car is worth in 20 years

1 answer

Aria's car is an example of exponential decay because Aria's car is losing value each year by a factor of 85% (or a decay factor of 0.85).

To create a sequence that describes the worth of Aria's car each year for 8 years, we start with the initial value of $36,000 and multiply by 0.85 (the remaining value after depreciation) for each subsequent year.

  1. Year 0: \( 36,000 \)
  2. Year 1: \( 36,000 \times 0.85 = 30,600.00 \)
  3. Year 2: \( 30,600 \times 0.85 = 26,010.00 \)
  4. Year 3: \( 26,010 \times 0.85 = 22,108.50 \)
  5. Year 4: \( 22,108.50 \times 0.85 = 18,791.23 \)
  6. Year 5: \( 18,791.23 \times 0.85 = 15,973.54 \)
  7. Year 6: \( 15,973.54 \times 0.85 = 13,579.51 \)
  8. Year 7: \( 13,579.51 \times 0.85 = 11,528.58 \)
  9. Year 8: \( 11,528.58 \times 0.85 = 9,791.29 \)

Now we can write the sequence of values for each year:

  • Year 0: $36,000.00
  • Year 1: $30,600.00
  • Year 2: $26,010.00
  • Year 3: $22,108.50
  • Year 4: $18,791.23
  • Year 5: $15,973.54
  • Year 6: $13,579.51
  • Year 7: $11,528.58
  • Year 8: $9,791.29

Next, we can create a formula for the worth of Aria's car over time using the exponential decay formula \(y = a \cdot b^x\).

Where:

  • \(a = 36,000\) (initial amount)
  • \(b = 0.85\) (decay factor)
  • \(x\) is the number of years

Thus, the formula becomes:

\[ y = 36,000 \cdot (0.85)^x \]

Now, let’s use this formula to find out how much Aria's car is worth in 20 years:

\[ y = 36,000 \cdot (0.85)^{20} \]

First, calculate \( (0.85)^{20} \):

\[ (0.85)^{20} \approx 0.038759 \]

Now, substitute this value back into the formula:

\[ y \approx 36,000 \cdot 0.038759 \approx 1395.24 \]

So, after 20 years, Aria's car will be worth approximately $1,395.24.