3, 12, 27, 48, ? — Number & Letter Series Aptitude Question
3, 12, 27, 48, ?: Find the next term: 3, 12, 27, 48, ? Answer and worked solution on CodeKairo.
- Topic: Number & Letter Series
- Section: Logical Reasoning
- Difficulty: Medium
- Time target: 60 seconds
Question
Find the next term:
3, 12, 27, 48, ?
Options
- 60
- 69
- 75
- 80
Show the answer and the worked solution
Correct answer: C. 75
Worked solution
- Dividing by 3 gives 1, 4, 9, 16 — the perfect squares.
- Next = 3 × 25 = 75.
Answer: 75.
The idea
Factoring out a common multiplier often reveals a familiar sequence underneath. Try dividing by the first term.
Shortcut. The gaps 9, 15, 21 rise by 6, so the next gap is 27 and 48 + 27 = 75.
Common trap. 69 — adding the last gap, 21, again (48 + 21); the gaps climb by 6, so the next is 27.