Pick the odd one:

Appeared in: HPSSC - 2015

Explanation

The core logic is to find a unique characteristic among the given options.
All four numbers (121, 144, 169, 196) are perfect squares of consecutive integers (11², 12², 13², 14²).
However, only 121 is a palindrome, meaning it reads the same forwards and backward.
The other numbers (144, 169, 196) are not palindromes.
This unique property makes 121 the odd one out in the group.

Option B: 144 is a perfect square (12²), but it is not a palindrome. This lack of palindromic property is shared with 169 and 196, so it is not the unique one.
Option C: 169 is a perfect square (13²), but like 144 and 196, it is not a palindrome. It doesn't have a unique property in this set.
Option D: 196 is a perfect square (14²), but it is not a palindrome. It fits the pattern of the other distractors, making it not the odd one out.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Odd One Out (Number Properties) as background academic context rather than a clinical decision trigger.
This question tests logical reasoning and pattern recognition, which are essential cognitive skills for nurses.
These skills are applied in clinical settings for interpreting data, identifying anomalies in patient conditions, and making sound clinical judgments.
What if the options were 121, 1331, 144, 169? In that case, 1331 is also a palindrome (and 11³), but the odd one out would likely still be based on squares vs. cubes or another distinguishing property.

How to Approach the Question

First, identify the task: find the 'odd one out' from the list of numbers.
Examine all four options to find a common pattern. Notice that 121=11², 144=12², 169=13², and 196=14². All are perfect squares.
Since being a perfect square is a shared property, look for a different property that makes one option unique.
Consider other mathematical characteristics like even/odd, prime numbers, sum of digits, or palindromes.
Check if any number is a palindrome (reads the same forwards and backward). Observe that 121 is a palindrome.
Verify that the other numbers (144, 169, 196) are not palindromes.

Concept Tested & Keywords

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Practise the full HPSSC - 2015

Attempt every question from this paper in a timed mock, then review the full solution for each one.