Analyzing Letter Sets to Find the Different One

This type of question asks us to find the letter set that does not follow the same pattern or rule as the other letter sets. To solve this, we usually look at the position of each letter in the English alphabet.

Let's assign a numerical value to each letter based on its position (A=1, B=2, C=3, ..., Z=26). Then, we will find the difference between the positions of consecutive letters in each set.

Examining Each Letter Set

Letter Set 1: HLNQU

• H is the 8th letter.
• L is the 12th letter. Difference: $12 - 8 = 4$.
• N is the 14th letter. Difference: $14 - 12 = 2$.
• Q is the 17th letter. Difference: $17 - 14 = 3$.
• U is the 21st letter. Difference: $21 - 17 = 4$.

The differences between consecutive letters in HLNQU are +4, +2, +3, +4.

Letter Set 2: BEHKN

• B is the 2nd letter.
• E is the 5th letter. Difference: $5 - 2 = 3$.
• H is the 8th letter. Difference: $8 - 5 = 3$.
• K is the 11th letter. Difference: $11 - 8 = 3$.
• N is the 14th letter. Difference: $14 - 11 = 3$.

The differences between consecutive letters in BEHKN are +3, +3, +3, +3.

Letter Set 3: UXADG

When the letters wrap around from Z back to A, we continue counting. Z is 26, A is 1, B is 2, etc.

• U is the 21st letter.
• X is the 24th letter. Difference: $24 - 21 = 3$.
• A is the 1st letter. Difference: From X (24) to Z (26) is +2, then Z (26) to A (1) is +1. Total difference: $2 + 1 = 3$. Or we can think $(1 - 24) \pmod{26} = -23 \pmod{26} = 3$.
• D is the 4th letter. Difference: $4 - 1 = 3$.
• G is the 7th letter. Difference: $7 - 4 = 3$.

The differences between consecutive letters in UXADG are +3, +3, +3, +3 (considering the wrap-around).

Letter Set 4: CFILO

• C is the 3rd letter.
• F is the 6th letter. Difference: $6 - 3 = 3$.
• I is the 9th letter. Difference: $9 - 6 = 3$.
• L is the 12th letter. Difference: $12 - 9 = 3$.
• O is the 15th letter. Difference: $15 - 12 = 3$.

The differences between consecutive letters in CFILO are +3, +3, +3, +3.

Comparing the Patterns

Let's summarize the differences found for each letter set in a table:

From the table, we can see that the letter sets BEHKN, UXADG, and CFILO all follow a consistent pattern where each letter is 3 positions after the previous one in the alphabet.

The letter set HLNQU, however, follows a different pattern (+4, +2, +3, +4). Therefore, HLNQU is the different letter set.

Conclusion

Based on the analysis of the patterns formed by the positions of the letters in the alphabet, the letter set HLNQU is the one that is different from the others.

Revision Table: Letter Pattern Analysis

Additional Information: Types of Letter Series Patterns

Letter series questions in reasoning can follow various patterns. Understanding common types can help solve problems faster.

• Alphabetical Position Increments/Decrements: The most common type, where consecutive letters have a fixed or a varying difference in their alphabetical positions, as seen in this problem.
• Skipping Letters: Patterns might involve skipping a fixed number of letters (e.g., A, D, G... skipping 2 letters each time).
• Vowel/Consonant Patterns: The series might follow a pattern based on vowels and consonants.
• Reverse Alphabetical Order: Letters might move backward in the alphabet.
• Combination of Patterns: Sometimes, a series might combine numerical patterns (like 1, 2, 3, 4...) with letter positions.
• Mirror Images/Symmetry: Less common, but some patterns can involve letters that are mirror images or symmetrical (e.g., A is symmetrical, B is not vertically).
• Meaningful Words/Sequences: Although less frequent in random letter sets like these options, some series might relate to days of the week, months, etc.

Practicing with different types of letter series helps in quickly identifying the underlying rule.