Understanding the Letter Series Problem

This question asks us to identify the missing term in a given series of letter groups. The series is: ADCB, FIHG, KNML, ?. To solve this, we need to find the pattern connecting the consecutive terms.

Let's look at the letters in each position within the four-letter groups. We will analyze the first letter of each term, then the second, and so on.

Analyzing the Pattern in the Letter Series

We will examine the progression of the letters at each corresponding position across the terms.

Pattern in the First Letter

The first letters of the terms are A, F, K, ?. Let's find their positions in the English alphabet:

• A is the 1st letter.
• F is the 6th letter.
• K is the 11th letter.

Let's find the difference in position:

• F (6) - A (1) = 5
• K (11) - F (6) = 5

The pattern for the first letter is an increase of 5 positions in the alphabet for each subsequent term. So, the first letter of the next term will be 5 positions after K.

K is the 11th letter. 11 + 5 = 16. The 16th letter is P.

The first letter of the missing term is P.

Pattern in the Second Letter

The second letters of the terms are D, I, N, ?. Let's find their positions in the English alphabet:

• D is the 4th letter.
• I is the 9th letter.
• N is the 14th letter.

Let's find the difference in position:

• I (9) - D (4) = 5
• N (14) - I (9) = 5

The pattern for the second letter is also an increase of 5 positions in the alphabet for each subsequent term. So, the second letter of the next term will be 5 positions after N.

N is the 14th letter. 14 + 5 = 19. The 19th letter is S.

The second letter of the missing term is S.

Pattern in the Third Letter

The third letters of the terms are C, H, M, ?. Let's find their positions in the English alphabet:

• C is the 3rd letter.
• H is the 8th letter.
• M is the 13th letter.

Let's find the difference in position:

• H (8) - C (3) = 5
• M (13) - H (8) = 5

The pattern for the third letter is an increase of 5 positions in the alphabet for each subsequent term. So, the third letter of the next term will be 5 positions after M.

M is the 13th letter. 13 + 5 = 18. The 18th letter is R.

The third letter of the missing term is R.

Pattern in the Fourth Letter

The fourth letters of the terms are B, G, L, ?. Let's find their positions in the English alphabet:

• B is the 2nd letter.
• G is the 7th letter.
• L is the 12th letter.

Let's find the difference in position:

• G (7) - B (2) = 5
• L (12) - G (7) = 5

The pattern for the fourth letter is an increase of 5 positions in the alphabet for each subsequent term. So, the fourth letter of the next term will be 5 positions after L.

L is the 12th letter. 12 + 5 = 17. The 17th letter is Q.

The fourth letter of the missing term is Q.

Combining the Patterns

Based on our analysis, the missing term should have:

• First letter: P
• Second letter: S
• Third letter: R
• Fourth letter: Q

Putting these letters together, the missing term is PSRQ.

Comparing with Options

Let's check the given options to see which one matches our derived term:

Option 1, PSRQ, matches the term we derived from the pattern. Therefore, PSRQ is the correct alternative to complete the series ADCB, FIHG, KNML, ?.

Revision Table: Letter Series Analysis

Combining the letters P, S, R, Q gives the next term PSRQ.

Additional Information on Letter Series and Reasoning

Letter series questions are common in logical reasoning and verbal ability tests. They require you to identify the rule or pattern that connects the terms in the series. Patterns can be based on various principles:

• Positional difference (like in this question, adding or subtracting a fixed number to the alphabetical position).
• Skipping letters (e.g., skipping one letter between terms).
• Alphabetical order (forward or backward).
• Combinations of letters forming meaningful sequences (though less common in simple series).
• Mirror images or reverse order within terms (like ADCB is reverse of ABCD, FIHG is reverse of FGHI). However, in this specific series, the *pattern between terms* is the +5 positional shift for each letter, not the internal reversal. The internal structure ADCB, FIHG, KNML, PSRQ shows that the last three letters are in reverse alphabetical order relative to each other (DCB, IHG, NML, SRQ), while the first letter follows a different pattern (A, F, K, P). The dominant pattern connecting the terms is the +5 shift in position for each corresponding letter.

To solve such problems effectively, it is helpful to know the alphabetical position of each letter quickly. Writing down the alphabet with numbers (A=1, B=2, ..., Z=26) can be useful during exams.