The odd one out in a list of squares — Aptitude Question
The odd one out in a list of squares: Which number does not belong? 4, 9, 16, 24, 36, 49 Answer and worked solution on CodeKairo.
- Topic: Number & Letter Series
- Section: Logical Reasoning
- Difficulty: Easy
- Time target: 40 seconds
Question
Which number does not belong?
4, 9, 16, 24, 36, 49
Options
- 9
- 16
- 24
- 36
Show the answer and the worked solution
Correct answer: C. 24
Worked solution
- 4 = 2², 9 = 3², 16 = 4², 36 = 6², 49 = 7².
- 24 is not a perfect square.
Answer: 24.
The idea
Test the small squares first in any odd-one-out question. Only one item should break the rule.
Shortcut. The roots run 2, 3, 4, ?, 6, 7, so the fourth slot should be 5² = 25 — the 24 sitting there is the intruder.
Common trap. 9 — the only odd number among the options, so it looks out of place on parity; but 9 = 3² fits the squares like the rest (49 is odd too).