Letter Pair Logic: Identifying the Odd One Out

This question asks us to find the letter-cluster pair that doesn't fit a pattern shared by the other three pairs. The pattern is based on the standard English alphabetical order.

Analyzing Letter Cluster Pairs

Let's look at each pair and the relationship between the letters based on their position in the alphabet (A=1, B=2, ..., Z=26).

Pair 1: LP-GJ

First Cluster (LP):

• L is the 12th letter.
• P is the 16th letter.
• The difference is $16 - 12 = 4$.

Second Cluster (GJ):

• G is the 7th letter.
• J is the 10th letter.
• The difference is $10 - 7 = 3$.

Pattern Observation: (+4, +3)

Pair 2: RV-MP

First Cluster (RV):

• R is the 18th letter.
• V is the 22nd letter.
• The difference is $22 - 18 = 4$.

Second Cluster (MP):

• M is the 13th letter.
• P is the 16th letter.
• The difference is $16 - 13 = 3$.

Pattern Observation: (+4, +3)

Pair 3: OS-JN

First Cluster (OS):

• O is the 15th letter.
• S is the 19th letter.
• The difference is $19 - 15 = 4$.

Second Cluster (JN):

• J is the 10th letter.
• N is the 14th letter.
• The difference is $14 - 10 = 4$.

Pattern Observation: (+4, +4)

Pair 4: IM-DG

First Cluster (IM):

• I is the 9th letter.
• M is the 13th letter.
• The difference is $13 - 9 = 4$.

Second Cluster (DG):

• D is the 4th letter.
• G is the 7th letter.
• The difference is $7 - 4 = 3$.

Pattern Observation: (+4, +3)

Pattern Recognition

By analyzing the difference between the alphabetical positions of the letters within each cluster of the pairs, we observe the following:

• Pairs 1 (LP-GJ), 2 (RV-MP), and 4 (IM-DG) consistently show a pattern where the first cluster has a difference of +4, and the second cluster has a difference of +3.

Odd Pair Determination

The pair OS-JN stands out because both clusters within it have a difference of +4.

• OS: $19 - 15 = 4$
• JN: $14 - 10 = 4$

This structure (+4, +4) differs from the (+4, +3) pattern seen in the other three pairs.

Conclusion

Therefore, the letter-cluster pair that does not belong to the group is OS-JN, as it follows a different alphabetical difference pattern.