The missing term of the following series is : DBC, KIJ, QOP,?, ZXY

Question

Accepted Answer

The correct option is 4:
$$Detailed explanation of why it is correct — include conceptual, or contextual depth.$$

The missing term in this alphabetical series, DBC, KIJ, QOP, ?, ZXY, can be determined by analyzing two distinct patterns: the internal arrangement of letters within each three-letter group and the progression of the first letter across the series. This type of question tests a student’s ability to decode complex coding rules.

First, let us examine the internal pattern of the letters within each term. If we look at the last two letters of each group, they consist of two consecutive letters in the English alphabet, but they are arranged in a specific, inverted order relative to the first letter.  * In DBC, the consecutive letters are B and C (B precedes C).
  * In KIJ, the consecutive letters are I and J (I precedes J).
  * In QOP, the consecutive letters are O and P (O precedes P).
  * In ZXY, the consecutive letters are X and Y (X precedes Y).
    In every case, the sequence of the consecutive letters (L2 and L3) is alphabetical, but the terms are arranged as (L1, L2, L3). This suggests the missing term must have consecutive letters in the second and third positions, where the second letter precedes the third alphabetically (e.g., T and U).Second, let us analyze the progression of the first letter of each term, converting letters to their corresponding alphabetical position (A=1, B=2, etc.):  * D (4) to K (11): The difference is $11 - 4 = +7$.
  * K (11) to Q (17): The difference is $17 - 11 = +6$.
  * This establishes a decreasing step pattern for the first letter: +7, +6, +5, +4.Following this established pattern, the first letter of the missing term must be Q plus 5 positions:  * Q (17) + 5 = V (22).
    To verify this, the next step should be V plus 4 positions:
  * V (22) + 4 = Z (26). Since Z (26) is the first letter of the final term ZXY, the progression V is correct for the first letter of the missing term.Now we combine both patterns. The missing term must start with V, and its last two letters must be consecutive, with the preceding letter first. Among the options, only **VTU** satisfies both conditions, as it starts with V, and T (20) and U (21) are consecutive letters, with T before U.

The incorrect option is 1:
The option VUW is incorrect because while it starts with the correct letter 'V', the last two letters, U (21) and W (23), are not consecutive in the alphabet; 'V' is missing between them. This violates the core internal pattern observed in every other term of the series.

The incorrect option is 2:
The option USV is incorrect on multiple grounds. Firstly, its first letter 'U' (21) does not follow the established sequence of increments (+7, +6, +5, +4), as the first letter should be V (22). Secondly, the last two letters, S (19) and V (22), are not consecutive, thus failing the internal pattern check as well.

The incorrect option is 3:
The option UTV is incorrect because its first letter 'U' (21) breaks the $+7, +6, +5, +4$ progression rule established by the first letters (D, K, Q). Although T (20) and U (21) are consecutive letters, the pattern requires the first letter to be V, not U.