Answer:
The sequence is geometric
The common ratio is 0.5
Explanation:
In the arithmetic sequence, there is a common difference between each two consecutive terms
In the geometric sequence, there is a common ratio between each two consecutive terms
Let us check the given sequence
∵ The first 3 terms are 12, 6, 3
∵ 6 - 12 = -6
∵ 3 - 6 = -3
∵ There is no common difference between the consecutive terms
∴ The sequence is not an arithmetic sequence
∵ 6 ÷ 12 = 0.5
∵ 3 ÷ 6 = 0.5
∴ There is a common ratio between each two consecutive terms
∴ The sequence is a geometric sequence
∴ The common ratio is 0.5