Fill the missing term in the mixed Roman–Arabic series: VI, 10, V, 11, __, 12, III, … Choose the entry that preserves the alternating Roman (decreasing) and Arabic (increasing) pattern.

Introduction / Context:
The series alternates between Roman numerals (descending by one each time) and Arabic numerals (ascending by one each time). Recognizing this interleaving quickly yields the missing value.

Given Data / Assumptions:

• Sequence: VI, 10, V, 11, ?, 12, III, …
• Roman track decreases 6, 5, 4, 3, …; Arabic track increases 10, 11, 12, …

Concept / Approach:
Separate the two interleaved subsequences and follow each trend independently.

Step-by-Step Solution:
Roman numerals at positions 1, 3, 5, 7: VI (6), V (5), next should be IV (4), then III (3).Arabic numerals at positions 2, 4, 6: 10, 11, 12 (increasing by 1).Therefore, the missing term at position 5 is IV.

Verification / Alternative check:
Interleaving the two lists yields the given sequence precisely when the blank is IV.

Why Other Options Are Wrong:

• II (2) / IX (9) / 14: Each breaks either the descending Roman-by-1 track or the alternating Roman–Arabic structure.

Common Pitfalls:
Forgetting to treat Roman numerals as numbers; converting to Arabic values clarifies the pattern.

Final Answer:
IV