Classification – Odd one out (letter–letter with numeric mean) In these alphanumeric items, the number equals the average (arithmetic mean) of the alphabet positions of the two letters. Three items follow this rule; one does not. Identify the exception.

Introduction / Context:
Alphanumeric classifications often tie letters to numbers via a consistent arithmetic (sum, difference, mean). Here, the embedded rule is the mean of positions (A=1 … Z=26). Spotting the arithmetic relation cleanly exposes the single misfit.

Given Data / Assumptions:

• KQ14, AY13, MR11, GW15
• Indexing: A=1, …, Z=26; mean = (pos(L1)+pos(L2))/2

Concept / Approach:
Compute the mean for each letter pair and compare with the trailing number. The outlier fails to match.

Step-by-Step Solution:
K(11), Q(17) → mean = (11+17)/2 = 14 → matches 14.A(1), Y(25) → mean = (1+25)/2 = 13 → matches 13.G(7), W(23) → mean = (7+23)/2 = 15 → matches 15.M(13), R(18) → mean = (13+18)/2 = 15.5 → does not match 11 → exception.

Verification / Alternative check:
The three conforming items also show symmetric spacing around their mean letter (e.g., K and Q around N). MR cannot map to an integer mean, reinforcing the mismatch.

Why Other Options Are Wrong:

• KQ14, AY13, GW15 → satisfy the mean rule exactly.
• None of these → there is a single mismatch (MR11).

Common Pitfalls:
Mistaking the rule for “difference” or “sum” instead of “mean,” which would not uniquely isolate the same item.

Final Answer:
MR11