From the following three letter groups, which one is the odd one out based on the alphabetical order pattern?

Introduction / Context:
This question asks you to identify the odd one out from groups of three letters. The pattern is based on the relative positions of letters in the English alphabet. Three of the options follow one consistent positional rule, while one option follows a different rule. The task is to analyse each group and determine which arrangement does not fit the common pattern.

Given Data / Assumptions:

• Letter groups: RQS, XWV, MLN, FEG and TSU.
• We consider alphabetical positions: A = 1, B = 2, ..., Z = 26.
• We compare the differences between consecutive letters within each group.
• Exactly one group will stand out by following a different pattern.

Concept / Approach:
Look at the first, second and third letters in each group and convert them to numerical positions. For RQS, the letters are R (18), Q (17) and S (19). The changes are minus 1 from R to Q and plus 2 from Q to S. For MLN, M (13), L (12) and N (14) again give minus 1 then plus 2. For FEG, F (6), E (5) and G (7) also follow minus 1 then plus 2. Thus these three groups share the same pattern: first to second letter is backward by one step, second to third letter is forward by two steps. Now examine XWV carefully to see if it fits or breaks this rule.

Step-by-Step Solution:

For RQS: R = 18, Q = 17, S = 19. Differences are -1 and +2. For MLN: M = 13, L = 12, N = 14. Differences are -1 and +2. For FEG: F = 6, E = 5, G = 7. Differences are -1 and +2. For XWV: X = 24, W = 23, V = 22. Differences are -1 and -1. Observe that XWV descends continuously, whereas the others move down then up.

Verification / Alternative check:
TSU would be T (20), S (19), U (21), which again is minus 1 then plus 2, so TSU matches the main pattern. The only group that does not follow minus 1 then plus 2 is XWV, which moves minus 1 and minus 1 again. Therefore, XWV forms a pure descending sequence instead of the mixed pattern and is the odd one out.

Why Other Options Are Wrong:
RQS, MLN, FEG and TSU all share the exact same positional change pattern, combining a backward step followed by a forward step. They are consistent with each other and therefore cannot be considered odd. The question requires the one option that breaks this shared rule, which is XWV.

Common Pitfalls:
A frequent error is to judge letter groups by rough visual order, such as assuming any group that looks nonstandard must be wrong. Another mistake is to look only at whether the sequence overall increases or decreases without checking the step size between each pair of letters. Writing down positions and differences systematically is the most reliable method.

Final Answer:
The only group that does not follow the minus 1 then plus 2 pattern is XWV, so it is the odd one out.