Find wrong number in series: 8, 12, 16, 27, 40.5, 60.75

Concept: In a wrong-number-in-series item, every term except one obeys a single consistent rule linking it to the previous term; the wrong term is the one that breaks this rule. Dividing consecutive terms here gives a constant ratio, so the governing rule is: each term = previous term × 3 ÷ 2 (i.e., × 1.5).

1. Find the rule from the first pair: 12 ÷ 8 = 1.5, so each term should equal the previous term × 1.5.

2. Apply the rule term by term: 8 × 1.5 = 12 — matches the series.

3. 12 × 1.5 = 18, but the series shows 16 in that position — this breaks the rule.

4. Continue with the rule-derived value (18), not the printed 16, to check the remaining terms: 18 × 1.5 = 27 — matches.

5. 27 × 1.5 = 40.5 — matches; 40.5 × 1.5 = 60.75 — matches.

Cross-check: Working backward from the last term confirms the same rule: 60.75 ÷ 1.5 = 40.5, 40.5 ÷ 1.5 = 27, 27 ÷ 1.5 = 18 (not 16) — consistent with the forward check.

Result: Since every term fits the rule except 16, which should be 18, the wrong number in the series is 16.