8, 24, 12, 36, 18, ? — Aptitude Question
8, 24, 12, 36, 18, ?: Find the next term: 8, 24, 12, 36, 18, ? Answer and worked solution on CodeKairo.
- Topic: Number & Letter Series
- Section: Logical Reasoning
- Difficulty: Medium
- Time target: 60 seconds
Question
Find the next term:
8, 24, 12, 36, 18, ?
Options
- 45
- 48
- 54
- 72
Show the answer and the worked solution
Correct answer: C. 54
Worked solution
- 8 × 3 = 24; 24 ÷ 2 = 12; 12 × 3 = 36; 36 ÷ 2 = 18.
- Next = 18 × 3 = 54.
Answer: 54.
The idea
Terms that rise and fall alternately point to two operations taking turns. Identify both before extending.
Shortcut. Split by position: 8, 12, 18 and 24, 36, ? each grow by × 1.5, so the blank is 36 × 1.5 = 54.
Common trap. 48 — reading 24, 36 as an arithmetic run and adding 12; the even-position terms grow by × 1.5, not by a fixed 12.