Answer:
[tex]a.\ \ \ V=15400(1-0.1)^t[/tex]
b. 2 yrs
Step-by-step explanation:
-Given the initial value at time t=0 as $15,400 and the decay rate as 10%.
-The exponential decay is given by the formula;
[tex]y=a(1-r)^x\\\\x-time\\r-decay \ rate\\a-initial \ value\\y-value \ at\ time \ x[/tex]
We can therefore write our decay expression as;
[tex]V=a(1-r)^t\\\\=15400(1-0.10)^t[/tex]
Hence, our exponential decay equation is [tex]V=15400(1-0.1)^t[/tex]
b. Having determined the decay function as [tex]V=15400(1-0.1)^t[/tex], we make $12465 our y value and solve for time, t;
[tex]V=15400(1-0.1)^t\\\\12465=15400(1-0.1)^t\\\\12465=15400(0.9^t)\\\\0.809416=0.9^t\\\\t=\frac{log \ 0.809416}{log \ 0.9}\\\\=2.0\ yrs[/tex]
Hence, the value of the car will be $12,465 after 2 years