You buy a new car for $\$ 24,000 .$ At the end of $n$ years, the value of your car is given by the sequence
$$
a_{n}=24,000\left(\frac{3}{4}\right)^{n}, \quad n=1,2,3, \ldots
$$
Find $a_{5}$ and write a sentence explaining what this value represents. Describe the $n$ th term of the sequence in terms of the value of your car at the end of each year.