Find the next number in the series: 11, 16, 23, 32, 43, ____?

Appeared in: RRB Staff Nurse Delhi-2015

Explanation

The core concept is identifying the pattern in a number series.
To find the pattern, calculate the difference between each consecutive pair of numbers in the series.
The differences are: 16-11=5, 23-16=7, 32-23=9, 43-32=11.
This reveals a secondary pattern: the difference itself increases by a constant value of 2 (5, 7, 9, 11...).
The next difference in this secondary pattern must be 11 + 2 = 13.
Adding this next difference to the last term of the original series gives the answer: 43 + 13 = 56.

Option B: Choosing 55 implies the next difference is 12 (55 - 43 = 12). This breaks the pattern of adding consecutive odd numbers (5, 7, 9, 11...).
Option C: Choosing 57 implies the next difference is 14 (57 - 43 = 14). This does not follow the pattern of adding odd numbers that increase by 2.
Option D: Choosing 54 implies the next difference is 11 (54 - 43 = 11). This incorrectly repeats the previous difference instead of increasing it to the next odd number, 13.

Visual 1: Flowchart: A visual breaking down the series. It would show the original numbers (11, 16, 23, 32, 43) on one line, and below it, arrows pointing between the numbers with the calculated differences (+5, +7, +9, +11). A final arrow would show +13 leading to the answer, 56. This helps visualize the two-level pattern.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Number Series Pattern Recognition as background academic context rather than a clinical decision trigger.
This type of question, while not clinical, assesses logical reasoning and pattern recognition, which are fundamental skills for nurses.
Nurses use pattern recognition daily to identify trends in a patient's vital signs, symptoms, or lab results, which can indicate improvement or deterioration.
Strong analytical skills are crucial for interpreting data, making sound clinical judgments, and anticipating patient needs.

How to Approach the Question

First, read the question carefully to understand you need to find the next number in the given sequence.
Calculate the difference between the first two numbers (16 - 11 = 5).
Calculate the difference between the next pairs of numbers (23 - 16 = 7; 32 - 23 = 9; 43 - 32 = 11).
Analyze the sequence of differences you've calculated (5, 7, 9, 11). Look for a pattern here. You should notice it's a series of consecutive odd numbers.
Determine the next number in the difference sequence (the next odd number after 11 is 13).
Add this next difference to the last number of the original series (43 + 13 = 56) to find the answer.

Concept Tested & Keywords

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Practise the full RRB Staff Nurse Delhi-2015

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