Three of the following letter-clusters are alike in some manner and hence form…
2023
Three of the following letter-clusters are alike in some manner and hence form a group. Which letter-cluster does not belong to that group?
Answer: C. LMO — Concept: every letter of the English alphabet carries a fixed position number (A = 1, B = 2, …, Z = 26) and an alphabetical mirror — the letter that stands…
- A.
OPK
- B.
ABY
- C.
LMO
- D.
IJQ
Attempted by 3 students.
Show answer & explanation
Correct answer: C
Concept: every letter of the English alphabet carries a fixed position number (A = 1, B = 2, …, Z = 26) and an alphabetical mirror — the letter that stands the same number of places from the opposite end. A letter at position n has its mirror at position 27 − n, which gives the pairs A–Z, B–Y, C–X and, at the centre, M–N. In a letter-cluster grouping question the shared rule is a fixed relation between these position numbers, and the cluster in which that relation breaks is the one that does not belong.
Application: write each cluster as position numbers, then test the mirror relation between its second and its third letter.
Cluster | Position numbers | Mirror of the 2nd letter (27 − n) | 3rd letter present |
|---|---|---|---|
OPK | 15, 16, 11 | 27 − 16 = 11 → K | K |
ABY | 1, 2, 25 | 27 − 2 = 25 → Y | Y |
LMO | 12, 13, 15 | 27 − 13 = 14 → N | O |
IJQ | 9, 10, 17 | 27 − 10 = 17 → Q | Q |
OPK, ABY and IJQ each close with the mirror of their own second letter, so those three share one rule and form the group. LMO closes with O, while the mirror of its second letter M is N, so LMO is the letter-cluster that does not belong.
Cross-check: because the second letter is one place after the first in every cluster, the same rule can be written as first position + third position = 26.
OPK: 15 + 11 = 26.
ABY: 1 + 25 = 26.
IJQ: 9 + 17 = 26.
LMO: 12 + 15 = 27, which breaks the sum.
Both formulations of the rule single out the same cluster, so the answer is LMO.