In the following pattern of ten letter strings YXYXYXZYX, YXYXYZXYX, YXYXZYXYX, YXYZXYXYX, YXZYXYXYX, ? a single letter Z changes position among the letters Y and X. Which of the following strings correctly comes next in the series?

Introduction / Context:
This is a positional pattern problem consisting of ten letter strings made up of Y, X, and a single Z. In each term, the letters Y and X are mostly stable, but the position of Z moves. The given terms are YXYXYXZYX, YXYXYZXYX, YXYXZYXYX, YXYZXYXYX, YXZYXYXYX, followed by a missing term. The goal is to detect the movement pattern of Z and predict its next position.

Given Data / Assumptions:

• Terms: YXYXYXZYX, YXYXYZXYX, YXYXZYXYX, YXYZXYXYX, YXZYXYXYX, ? • Length of each string is nine characters. • Exactly one Z appears in each string, with the remaining characters being Y or X. • Options: ZYXYXYXYX, YXYXYXZYX, YZXYXYXYX, YXYXYZXYX.

Concept / Approach:
We number the positions from left to right and track only the position of Z. Alphabet test series of this kind often place a special symbol that travels one step at a time across the string. By listing the position numbers of Z in each term, we can spot a simple pattern such as leftward movement and then find its next position. The remaining Y and X letters simply fill the other slots consistently.

Step-by-Step Solution:
Step 1: Label positions from 1 to 9 for each term. Step 2: In YXYXYXZYX, Z appears at position 7 (counting from the left). Step 3: In YXYXYZXYX, Z is at position 6. Step 4: In YXYXZYXYX, Z is at position 5. Step 5: In YXYZXYXYX, Z is at position 4. Step 6: In YXZYXYXYX, Z is at position 3. Step 7: We can now see that Z is moving left by one position each time: 7, 6, 5, 4, 3. Therefore, in the next term it should move to position 2. Step 8: A string that has Z at position 2 and preserves the Y and X structure is YZXYXYXYX.

Verification / Alternative check:
Writing Z position sequence explicitly as 7, 6, 5, 4, 3, ? makes the pattern obvious as a simple decreasing sequence. The next value must be 2. Among the answer choices, ZYXYXYXYX has Z at position 1, YXYXYXZYX puts Z back at position 7, and YXYXYZXYX repeats an earlier term with Z at position 6. Only YZXYXYXYX has Z at position 2 and fits the idea that Z is moving left one step at a time.

Why Other Options Are Wrong:
ZYXYXYXYX moves Z too far to the left to position 1, skipping the intermediate position 2, so it does not follow the consistent one step pattern. YXYXYXZYX corresponds to the first term and would mean that Z jumps back to position 7, which is inconsistent with the smooth leftward progression. YXYXYZXYX is already present as the second term in the series and therefore cannot be the new next term.

Common Pitfalls:
Some learners attempt to track Y and X patterns instead of focusing on Z, which is unnecessary and confusing. Others do not count positions carefully and misidentify where Z is located. To avoid mistakes, always label positions explicitly and track only the special letter, because that is usually where the pattern lies in such questions.

Final Answer:
The correct next term in the series is YZXYXYXYX.