Answer
$a_{8} = 0.004$
Work Step by Step
The nth term of a geometric sequence can be found using the formula:
$a_n=a_1(r^{n-1})$
where
r= common ratio
$a_1$ = first term
$a_n$ = nth term
n = term number
Substitute the given values of $a_1$, n, and $r$ to find:
$a_{8}=40,000(0.1)^{8-1}
\\a_{8}=40,000(0.1)^{7}
\\a_{8}=40,000 (0.0000001)
\\a_{8} = 0.004$
