Answer
$0.004$
Work Step by Step
The general formula to find the nth term of a Geometric sequence is given as: $ a_{n}=a_1r^{n-1}$
We are given that $ a_1=40,000; r=0.1; n=8$
Now, $ a_{8}=40,000 \times (0.1)^{8-1}=40,000 \times (0.1)^{7}$
$\implies a_{8}=0.004$