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Question

Which letter cluster will replace the question mark (?) to complete the given series?

CBOM, FCQN, ?, LEUP, OFWQ

The correct answer is

IDSO

Solving Letter Series Completion Problems

Letter series questions require identifying the pattern that connects consecutive terms in the given sequence. This pattern can involve addition, subtraction, multiplication, division, or a combination of operations on the alphabetical positions of the letters, or sometimes patterns based on letter properties like vowels/consonants or symmetry.

Let's analyze the given letter series: CBOM, FCQN, ?, LEUP, OFWQ

We need to find the letter cluster that replaces the question mark (?). To do this, we will examine the pattern for each letter position within the clusters.

Analyzing the Pattern in the Letter Series

We look at the first letter of each cluster, then the second letter, and so on.

First Letter Analysis

The first letters are C, F, ?, L, O.

  • C is the 3rd letter of the alphabet.
  • F is the 6th letter of the alphabet.
  • L is the 12th letter of the alphabet.
  • O is the 15th letter of the alphabet.

Let's look at the differences in their positions:

  • F - C: \(6 - 3 = 3\)
  • O - L: \(15 - 12 = 3\)

The pattern for the first letter seems to be an addition of 3 to the alphabetical position of the previous letter. So, the first letter of the missing cluster should be \(6 + 3 = 9\)th letter, which is I.

Second Letter Analysis

The second letters are B, C, ?, E, F.

  • B is the 2nd letter.
  • C is the 3rd letter.
  • E is the 5th letter.
  • F is the 6th letter.

Let's look at the differences:

  • C - B: \(3 - 2 = 1\)
  • F - E: \(6 - 5 = 1\)

The pattern for the second letter is an addition of 1 to the alphabetical position of the previous letter. So, the second letter of the missing cluster should be \(3 + 1 = 4\)th letter, which is D.

Third Letter Analysis

The third letters are O, Q, ?, U, W.

  • O is the 15th letter.
  • Q is the 17th letter.
  • U is the 21st letter.
  • W is the 23rd letter.

Let's look at the differences:

  • Q - O: \(17 - 15 = 2\)
  • W - U: \(23 - 21 = 2\)

The pattern for the third letter is an addition of 2 to the alphabetical position of the previous letter. So, the third letter of the missing cluster should be \(17 + 2 = 19\)th letter, which is S.

Fourth Letter Analysis

The fourth letters are M, N, ?, P, Q.

  • M is the 13th letter.
  • N is the 14th letter.
  • P is the 16th letter.
  • Q is the 17th letter.

Let's look at the differences:

  • N - M: \(14 - 13 = 1\)
  • Q - P: \(17 - 16 = 1\)

The pattern for the fourth letter is an addition of 1 to the alphabetical position of the previous letter. So, the fourth letter of the missing cluster should be \(14 + 1 = 15\)th letter, which is O.

Combining the Results

By combining the letters found for each position, we get the missing letter cluster:

  • First letter: I
  • Second letter: D
  • Third letter: S
  • Fourth letter: O

The missing cluster is IDSO.

Verification of the Pattern

Let's check if the pattern holds true for the next term (LEUP) using our derived cluster IDSO:

  • I to L: \(9 + 3 = 12\) (L) - Correct
  • D to E: \(4 + 1 = 5\) (E) - Correct
  • S to U: \(19 + 2 = 21\) (U) - Correct
  • O to P: \(15 + 1 = 16\) (P) - Correct

The pattern is consistent throughout the series.

Summary of the Pattern

Position Pattern (Addition to previous letter's position)
First Letter +3
Second Letter +1
Third Letter +2
Fourth Letter +1

The letter cluster that replaces the question mark (?) is IDSO.

Revision Table: Letter Series Patterns

Pattern Type Description Example Logic
Arithmetic Progression Positions increase or decrease by a constant value. A(+2)C(+2)E... (Positions +2)
Alternating Progression Different patterns applied to alternate terms or positions. A(+1)B(+2)D(+1)E... (Positions +1, then +2, then +1...)
Positional Shift Letters shifted by a fixed number of places. A (+3 positions) D
Mixed Patterns A combination of different logic across positions or terms. First letter +1, second letter +2, etc.

Additional Information: Tips for Letter Series Questions

  • Write down the alphabetical positions of the letters if needed.
  • Look for patterns in differences between consecutive letters' positions.
  • Consider patterns that alternate between adding/subtracting different numbers.
  • Check if the pattern involves skipping letters or repeating sequences.
  • Verify the pattern for the entire given series before deciding on the missing term.
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Important Questions from Alphabet Series

  1. Select the letter-cluster from among the given options that can replace the question mark (?) in the following series.

    KMTC, EVOM, OQXG, IZSQ, ?

  2. Select the set of letters that when sequentially placed in the blanks of the given letter series will complete the series.

    k_lmml_mk_mmk_lkkl_m
  3. Select the letter will replace the question mark (?) in the following series.

    C, B, B, C, Z, E, W, H, S, ?, N
  4. Which letter will replace the question mark (?) in the following letter series?

    E, J, N, Q, S, ?

  5. Select the combination of letters that when sequentially placed in the blanks of the given series will complete the series.
    C _ B N _ _ V_ _ H C _ B _ H

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