Which pair of letters will correctly fill the blanks in the series: Z, X, V, T, R, __, __?

Introduction / Context:
This letter series question asks you to extend a pattern built on regular movements through the alphabet. It is a classic descending sequence with a fixed step size and tests your understanding of alphabetical positions and simple subtraction.

Given Data / Assumptions:

• Letters given: Z, X, V, T, R, __, __.
• Two consecutive letters are missing at the end.
• The pattern is most likely based on constant jumps between letters.

Concept / Approach:
Map each letter to its position in the alphabet, then compute the differences between consecutive terms. For a simple reasoning question, the step size is usually constant, such as minus two or plus three. Once the step is clear, you can extend the sequence by applying the same operation for the missing terms.

Step-by-Step Solution:
Step 1: Convert letters to positions: Z = 26, X = 24, V = 22, T = 20, R = 18. Step 2: Compute differences: 26 to 24 is -2, 24 to 22 is -2, 22 to 20 is -2, 20 to 18 is -2. Step 3: A consistent pattern emerges: at each step, we move two positions backward in the alphabet. Step 4: Continue the pattern after R (position 18). Subtract 2: 18 - 2 = 16, which is P. Step 5: For the next missing letter, again subtract 2: 16 - 2 = 14, which is N. Step 6: Therefore the missing pair of letters is P, N.

Verification / Alternative check:
Rebuild the complete sequence using the pattern: Z (26), X (24), V (22), T (20), R (18), P (16), N (14). Each move is exactly two steps backward in the alphabet, confirming a perfect and simple pattern. No step violates the constant difference rule, which verifies that P and N are the correct letters.

Why Other Options Are Wrong:
The other options introduce letters whose positions do not follow the -2, -2, -2 pattern from the preceding term. For instance, M and N are 13 and 14, which do not follow directly from R (18) by a consistent step size. Similarly, O and K or K and S produce jumps of mixed sizes, breaking the clean arithmetic progression in letter positions.

Common Pitfalls:
Some candidates mistakenly attempt to assign individual patterns to each missing position without extending the global rule. Another error is failing to translate letters into numbers, which hides the simple subtraction pattern. Always work in terms of positions for these letter sequences to make the arithmetic obvious.

Final Answer:
The two letters that correctly continue the pattern are P, N.