Select the letter-series which follows the rule: "Number of letters skipped in between adjacent letters in the series doubles every time."?

Appeared in: RRB Staff Nurse Delhi-2015

Explanation

The question requires identifying a letter series where the count of skipped letters between adjacent letters doubles each time.
In the series BDGLU, the number of letters skipped are: B (C) D, D (EF) G, G (HIJK) L, L (MNOPQRST) U.
The count of skipped letters is 1, 2, 4, 8.
This sequence (1, 2, 4, 8) perfectly follows the rule, as each subsequent number is double the previous one (1x2=2, 2x2=4, 4x2=8).

Option A: The number of skipped letters in ADIPY is 2, 4, 6, 8. This pattern is not a consistent doubling sequence; while the jump from 2 to 4 is a doubling, the jump from 4 to 6 is not.
Option C: The series EGJOF initially follows the pattern (1, 2, 4 skipped letters), but the last step from O to F moves backward in the alphabet, breaking the progressive pattern entirely.
Option D: The number of skipped letters in GJNSY is 2, 3, 4, 5. This is a simple arithmetic progression where the gap increases by one each time, not doubles.

Visual 1: Flowchart: 'How to Solve Letter Series Problems'. This would show the steps: 1. Read the rule carefully. 2. Assign numerical positions to letters in an option. 3. Calculate the number of skipped letters between each pair. 4. Check if the sequence of skipped letters matches the rule. 5. Repeat for all options.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Pattern recognition in letter series (geometric progression) as background academic context rather than a clinical decision trigger.
This question tests logical reasoning and pattern recognition, which are fundamental cognitive skills.
In nursing, these skills are crucial for interpreting trends in a patient's vital signs, recognizing patterns in lab results over time, and identifying subtle changes in a patient's condition that may signal improvement or deterioration.
What if the rule was 'number of letters skipped is consecutive prime numbers'? Then a series like 'ACFIL' (skipping 1, 2, 4, 6 letters) would be incorrect, but a series like 'ADGJM' (skipping 2, 2, 2, 2 letters) would also be incorrect. A correct series would be something like 'ACFJ' (skipping 1, 2, 3 letters - wait, prime numbers are 2, 3, 5, 7... so a series like 'ADGLS' skipping 2, 3, 5, 7 letters would be correct).

How to Approach the Question

First, clearly understand the rule provided: 'Number of letters skipped in between adjacent letters in the series doubles every time'.
Take the first option (ADIPY) and analyze the gaps. A to D skips 2 letters (B, C). D to I skips 4 letters (E,F,G,H). I to P skips 6 letters (J,K,L,M,N,O). The sequence of skips is 2, 4, 6. This is not a doubling pattern (4 is double 2, but 6 is not double 4). So, eliminate this option.
Analyze the second option (BDGLU). B to D skips 1 letter (C). D to G skips 2 letters (E, F). G to L skips 4 letters (H,I,J,K). L to U skips 8 letters. The sequence of skips is 1, 2, 4, 8. This perfectly matches the doubling rule.
Confirm this is the correct answer by quickly checking the other options to ensure no other series fits the rule.
Option GJNSY has skips of 2, 3, 4, 5 (arithmetic progression).
Option EGJOF breaks the pattern by reversing direction.

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.