42,40,38,35,33,31,28, what comes after?

Appeared in: Maharashtra CHO - 2020

Explanation

The series follows a repeating subtraction pattern of -2, -2, -3.
This is evident by calculating the difference between consecutive numbers: 42-2=40, 40-2=38, 38-3=35, and so on.
The last given step is 31 - 3 = 28, which completes one of the (-2, -2, -3) cycles.
To find the next number, the pattern restarts. We subtract 2 from the last number: 28 - 2 = 26.
To find the second number, we apply the next step in the pattern, which is again subtracting 2: 26 - 2 = 24.

Option A: This option results from an incorrect pattern assumption, possibly subtracting 3 twice (28-3=25, 25-3=22), which does not match the established -2, -2, -3 cycle.
Option B: While the first number, 26, is correct (28-2), the second number, 23, is incorrect. It results from subtracting 3 (26-3) instead of the correct next step in the pattern, which is subtracting 2.
Option D: This option is incorrect because it starts by subtracting 3 from 28 (28-3=25), which is not the next step in the repeating -2, -2, -3 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.
While not a clinical question, logical reasoning and pattern recognition are fundamental skills for nurses.
These skills are essential for interpreting trends in patient data, such as vital signs or lab results, to recognize early signs of deterioration and make timely decisions.
For example, a nurse might observe a pattern of gradually decreasing urine output and rising creatinine levels, indicating a potential acute kidney injury.

How to Approach the Question

First, carefully read the sequence of numbers provided: 42, 40, 38, 35, 33, 31, 28.
Calculate the difference between each consecutive pair of numbers to identify the underlying rule.
Observe the differences: (42-40=2), (40-38=2), (38-35=3), (35-33=2), (33-31=2), (31-28=3).
Recognize that there is a repeating pattern of operations: subtract 2, subtract 2, subtract 3.
Apply this identified pattern to the last number in the series (28) to predict the next terms.
Since the last operation was -3, the pattern restarts with -2. So, 28 - 2 = 26. The next operation is also -2. So, 26 - 2 = 24.

Concept Tested & Keywords

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Practise the full Maharashtra CHO - 2020

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