Question

Lana bought a sports car for $75,700. If the value of her car decreases 4.3% annually.

Answer 1

Given:

The initial value of the car = $75,700

Decreasing rate = 4.3%

To find:

The value of r in the exponential DECAY formula.

Solution:

The exponential decay formula is:

$y=a(1-r)^t$

Where, a is the initial value, r is the rate of decay on decimal and t is the time period.

The initial value of the car is $75,700 and its value decreases 4.3% annually. So,

$a=75,700$

$r=\dfrac{4.3}{100}$

$r=0.043$

The required exponential decay formula is:

$y=75,700(1-0.043)^t$

Therefore, the value of r in the exponential decay formula is 0.043.