From the letter groups JGD, NLI, XUR and QNK, which set of three letters is the odd one out based on the positional differences in the alphabet?

Introduction / Context:
This question involves groups of three letters: JGD, NLI, XUR and QNK. You are asked to identify which group is the odd one out. The solution depends on the positions of the letters in the English alphabet and how those positions change from one letter to the next within each group.

Given Data / Assumptions:
The letter groups are:

• JGD
• NLI
• XUR
• QNK

We assume that three of these groups share the same pattern of positional differences between consecutive letters, while one group breaks this pattern.

Concept / Approach:
To solve, we convert each letter to its numerical position in the alphabet (A = 1, B = 2, ..., Z = 26) and then calculate the differences between the first and second letters, and between the second and third letters in each group. If most groups show the same constant negative difference (for example, minus three) for both steps, then the group that does not will be the odd one out.

Step-by-Step Solution:
Step 1: JGD. J is 10, G is 7, D is 4. The differences are 10 → 7 (−3) and 7 → 4 (−3).Step 2: XUR. X is 24, U is 21, R is 18. The differences are 24 → 21 (−3) and 21 → 18 (−3).Step 3: QNK. Q is 17, N is 14, K is 11. The differences are 17 → 14 (−3) and 14 → 11 (−3).Step 4: NLI. N is 14, L is 12, I is 9. The differences are 14 → 12 (−2) and 12 → 9 (−3).Step 5: We see that in JGD, XUR and QNK, both steps reduce the letter position by 3. In NLI, the first step reduces by 2 instead of 3.

Verification / Alternative check:
We can summarise the pattern as follows: the groups JGD, XUR and QNK all have the shape (x, x − 3, x − 6) in terms of alphabetical positions. For example, JGD is 10, 7, 4; XUR is 24, 21, 18; QNK is 17, 14, 11. In contrast, NLI is 14, 12, 9, which corresponds to 14, 12, 9, with differences of −2 and −3. This group clearly breaks the constant difference of −3 in the first step.

Why Other Options Are Wrong:
JGD, XUR and QNK all demonstrate a consistent pattern: each letter is three places earlier in the alphabet than the previous letter. Removing any of them as the odd one would ignore this clear regularity and leave NLI, which does not follow the rule, still in the set. Hence, those groups are not valid choices as the odd one out.

Common Pitfalls:
Students may look for symmetrical positions or vowel consonant patterns instead of computing exact numerical differences. It is important to systematically map letters to their alphabetical positions and then calculate the differences, as this often reveals a simple and precise pattern that is not obvious at first glance.

Final Answer:
The group that does not follow the consistent minus three pattern is NLI.