Fill the blank in the following series-
6, 30, 60, 300, 600 __

Appeared in: AIIMS CRE SNO - 2023

Explanation

The series follows a recurring pattern of two mathematical operations: multiplication by 5 and multiplication by 2.
The first number (6) is multiplied by 5 to get the second number (30).
The second number (30) is then multiplied by 2 to get the third number (60).
This alternating pattern (×5, ×2) continues throughout the series.
To find the missing term, the last known number (600) must be multiplied by 5, which is the next operation in the sequence, resulting in 3000.

Option A: This is the fourth number in the series, not the next one. It incorrectly repeats a previous term instead of continuing the established pattern.
Option C: This is the last given number in the series. Choosing this would imply the pattern stops or the next operation is to multiply by 1, which is inconsistent with the established alternating pattern of ×5 and ×2.
Option D: This result (1200) is obtained by multiplying 600 by 2. This is incorrect because the pattern dictates that after a '×2' operation (which resulted in 600), the next operation must be '×5'.

Visual 1: Flowchart. A flowchart illustrating the sequence: Start with 6, an arrow labeled '×5' points to 30, an arrow labeled '×2' points to 60, an arrow labeled '×5' points to 300, an arrow labeled '×2' points to 600, and a final arrow labeled '×5' points to 3000.

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 this is a general aptitude question, strong numerical reasoning is a key nursing skill.
It is essential for accurate medication dosage calculations, titrating IV drips, and interpreting trends in patient data (like vital signs or lab results) over time.
What if? If a patient's lab value was following this pattern over several hours, a nurse who recognizes the trend could anticipate the next value, potentially alerting the medical team to a significant change before it becomes critical.

How to Approach the Question

First, examine the relationship between the first two numbers (6 and 30). The operation is likely multiplication by 5.
Next, check the relationship between the second and third numbers (30 and 60). The operation is multiplication by 2.
Verify if this '×5, ×2' pattern continues for the rest of the given series. (60 × 5 = 300; 300 × 2 = 600).
Since the pattern holds true, apply the next logical operation in the sequence (×5) to the last number (600).
Calculate 600 × 5 to arrive at the final answer, 3000.
Match your result with the given options.

Concept Tested & Keywords

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Practise the full AIIMS CRE SNO - 2023

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