(Note: The odd one out is not based on the number of consonants/vowels or their position in the letter-cluster.)
The objective is to find the letter-cluster pair that deviates from a specific pattern shared by the others. This pattern relates to the alphabetical order of letters.
The commonality among three of the options lies in the consistency of the alphabetical difference between the letters within each of the two pairs presented in an option. We calculate this difference for each pair and check for consistency within the option.
Alphabetical positions are assigned as A=1, B=2, ..., Z=26.
| Option | Pair 1 Difference | Pair 2 Difference | Consistency |
|---|---|---|---|
| 1. DI - AF | P(I) - P(D) = $9 - 4 = 5$ | P(F) - P(A) = $6 - 1 = 5$ | Consistent (Both 5) |
| 2. XB - UY | P(B) - P(X) = $2 - 24 \equiv 4 \pmod{26}$ | P(Y) - P(U) = $25 - 21 = 4$ | Consistent (Both 4) |
| 3. QR - MP | P(R) - P(Q) = $18 - 17 = 1$ | P(P) - P(M) = $16 - 13 = 3$ | Inconsistent (1 $\neq$ 3) |
| 4. KO - HL | P(O) - P(K) = $15 - 11 = 4$ | P(L) - P(H) = $12 - 8 = 4$ | Consistent (Both 4) |
Three options (1, 2, and 4) share the characteristic that both letter-cluster pairs within them have the same internal alphabetical difference. Option 3 is the outlier because its pairs have different internal differences (1 and 3).