Mark bought a brand new car for $35,000 in 2008. If the car depreciates in value approximately 8% each year, write an exponential function to model the situation. Then, find the value of the car in 2015. Is this considered growth or decay?

Decay function

The value of the car in 2015 is $19,525.

Step-by-step explanation:

A exponential value function has the following format:

In which V(t) is the value after t years, V(0) is the initial value and 1+r is the yearly variation rate.

If 1+r>1, the function is a growth function.

If 1-r<1, the function is a decay function.

Mark bought a brand new car for $35,000 in 2008.

This means that

If the car depreciates in value approximately 8% each year

Depreciates, then r is negative. So

Then

0.92 < 1, so decay function.

Then, find the value of the car in 2015.

2015 is 2015-2008 = 7 years after 2008. So this is V(7).

The value of the car in 2015 is $19,525.