36, 54, 18, 27, 9, 18.5, 4.5

Question:
36, 54, 18, 27, 9, 18.5, 4.5

[A].

4.5

[B].

18.5

[C].

54

[D].

18

Answer: Option B

Explanation:

The terms are alternatively multiplied by 1.5 and divided by 3. However, 18.5 does not satisfy it.