Find the next number in this series ?

2,4,8,16

Appeared in: NORCET 9 Prelims-2025

Explanation

The question requires identifying the pattern in the number series 2, 4, 8, 16 to find the subsequent number.
This series is a classic example of a geometric progression, where each term is obtained by multiplying the preceding term by a constant factor, known as the common ratio.
Observing the series, 4 is 2 multiplied by 2, 8 is 4 multiplied by 2, and 16 is 8 multiplied by 2. The common ratio is 2.
To find the next term, the last term (16) is multiplied by the common ratio (2), which results in 32.
Alternatively, the series represents powers of 2, starting from 2¹, 2², 2³, 2⁴. The next term is 2⁵, which equals 32.

Option A: This number does not fit the established pattern of multiplying by 2. It seems to be an arbitrary number.
Option B: This is the last term given in the series, not the next term. The question asks for the number that follows 16.
Option C: This number does not follow the geometric progression of multiplying by 2. It is an incorrect calculation.

Visual 1: Flowchart - A flowchart illustrating the progression of the series. It would show '2', an arrow labeled '× 2' pointing to '4', another arrow labeled '× 2' pointing to '8', and so on, ending with an arrow from '16' pointing to a box with '32'.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Number Series (Geometric Progression) as background academic context rather than a clinical decision trigger.
While this is a general aptitude question, strong numerical and logical reasoning skills are fundamental in nursing.
Nurses constantly use mathematical skills for tasks like calculating drug dosages, titrating IV drips, and interpreting lab values, where a simple calculation error can have serious consequences for patient safety.
What if the series was 2, 4, 6, 8? This would be an arithmetic progression with a common difference of 2. The next number would be 10 (8 + 2), not 16. Recognizing the type of progression (arithmetic vs. geometric) is key.

How to Approach the Question

First, read the question carefully to understand the task, which is to find the next number in a given sequence.
Analyze the relationship between the consecutive numbers in the series (2, 4, 8, 16).
Check for a common difference (arithmetic progression) or a common ratio (geometric progression). Here, 4/2 = 2, 8/4 = 2, 16/8 = 2. This confirms a geometric progression with a common ratio of 2.
Apply the identified rule to the last number in the series to find the next term. Multiply 16 by 2.
Calculate the result: 16 × 2 = 32.
Compare your result with the given options and select the matching one.

Concept Tested & Keywords

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Practise the full NORCET 9 Prelims-2025

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