Answer:
see explanation
Step-by-step explanation:
Note there is a common ratio r between consecutive terms in the sequence, that is
r = 80 ÷ 320 = 20 ÷ 80 = 5 ÷ 20 = 1.25 ÷ 5 = 0.25
Thus the sequence is geometric.
A recursive rule allows a term in the sequence to be found by multiplying the previous term by r, thus
[tex]a_{n}[/tex] = 0.25[tex]a_{n-1}[/tex] with a₁ = 320
