Difficulty: Medium
Correct Answer: SVI
Explanation:
Introduction / Context:
This question comes from alphabet sequence and pattern recognition, a common topic in aptitude tests. You are given a non standard sequence of letters and a derived pattern in the form of three letter groups such as NDP, QWB and ZFR. The task is to identify the underlying positional rule that links each letter of these groups to the master sequence and then extend the series to find the next group. Success in these problems depends on quickly finding steady jumps or arithmetic relationships between positions.
Given Data / Assumptions:
1) The special sequence is: N O P Q Y B Z A R S H I J K L M T U V G F E W X D C.2) The three letter groups provided are NDP, QWB and ZFR.3) The groups are formed by selecting letters at certain positions in this sequence according to a fixed rule.4) We must determine the pattern and use it to find the next group after ZFR.
Concept / Approach:
The simplest approach is to number the letters of the special sequence from left to right and then mark the positions of N, D, P, Q, W, B, Z, F and R. Once the positions are known, you can look for numeric patterns, such as constant differences between positions of first letters, second letters and third letters across successive groups. When you discover a consistent jump pattern, you can add the same changes to the last known positions to get the positions of the next group and thus its letters.
Step-by-Step Solution:
1) Number the sequence: 1 N, 2 O, 3 P, 4 Q, 5 Y, 6 B, 7 Z, 8 A, 9 R, 10 S, 11 H, 12 I, 13 J, 14 K, 15 L, 16 M, 17 T, 18 U, 19 V, 20 G, 21 F, 22 E, 23 W, 24 X, 25 D, 26 C.2) Find positions for each letter in NDP: N is at 1, D is at 25, P is at 3. So the positions are 1, 25 and 3.3) For QWB: Q is at 4, W is at 23, B is at 6. Positions are 4, 23 and 6.4) For ZFR: Z is at 7, F is at 21, R is at 9. Positions are 7, 21 and 9.5) Look at first letters positions: 1, 4, 7. The change is +3 each time, so the next first letter should be at position 10.6) Look at second letters positions: 25, 23, 21. The change is −2 each time, so the next second letter should be at position 19.7) Look at third letters positions: 3, 6, 9. The change is +3 each time, so the next third letter should be at position 12. Position 10 holds S, position 19 holds V and position 12 holds I. Hence, the next group is SVI.
Verification / Alternative check:
An additional check is to verify that there is no alternative pattern that fits as neatly. The arithmetic differences between positions of first, second and third letters are consistent across the three initial groups and lead naturally to the next positions 10, 19 and 12. When you map these positions back to letters in the special sequence, you get S, V and I respectively. Since no other systematic interpretation explains all three original groups as cleanly, this confirms that SVI is the correct continuation of the pattern.
Why Other Options Are Wrong:
AFS, IVS and SFA all use letters from the special sequence but do not correspond to the positions obtained by applying the +3, −2 and +3 jumps.They either break the consistent position differences or rearrange letters in a way that does not match the established pattern.None of these is incorrect because SVI exactly fits the positional rule derived from the earlier terms.
Common Pitfalls:
Candidates sometimes attempt to work with alphabetical positions (A as 1, B as 2, and so on) rather than positions within the given special sequence, which leads to completely different and incorrect jumps. Others forget that each of the three positions in a group may follow its own separate numeric pattern. A few test takers only look at the first letters and ignore the second and third letters, resulting in incomplete or wrong answers. Always treat each column of letters as its own mini sequence and confirm that a single consistent rule applies before deciding the next group.
Final Answer:
The next three letter group in the series based on the given special sequence is SVI.
Discussion & Comments