Answer: [tex]\bold{a_n=120\bigg(\dfrac{1}{3}\bigg)^{n-1}}[/tex]
Step-by-step explanation:
[tex]\text{A geometric sequence is represented by:}\ a_n = a_1 (r)^{n-1}\\\text{where}\ a_1\ \text{is the first term, r is the common ratio, and n is the term}[/tex]
[tex]\text{In the given sequence,}\ a_1=120\ \text{and r} = \dfrac{40}{120}=\dfrac{1}{3}[/tex]
[tex]\rightarrow \ a_n=120\bigg(\dfrac{1}{3}\bigg)^{n-1}[/tex]
