Spot the odd entry in the alternating pattern: 5, 16, 6, 16, 7, 16, 7, 16, 9.

Introduction / Context:
This sequence alternates between a changing value and a fixed value (16). The non-16 terms should form a simple increasing run, but there is a discrepancy. Identifying the intended pattern reveals which non-16 entry is incorrect.

Given Data / Assumptions:

• Positions 1,3,5,7,9 (odd positions) are: 5, 6, 7, 7, 9
• Positions 2,4,6,8 (even positions) are constant: 16, 16, 16, 16
• Natural intended pattern for odd positions is a steady increase: 5, 6, 7, 8, 9

Concept / Approach:
Check the odd-position subsequence independently. If the design is to increment by 1 at each odd position, the fourth odd position should be 8, not 7. Hence, the duplicate 7 violates the pattern and is the odd term.

Step-by-Step Solution:
Extract odd positions: [5, 6, 7, 7, 9]Expected: [5, 6, 7, 8, 9]Mismatch at the fourth odd position ⇒ value should be 8 but is 7Therefore, the erroneous entry is “7” (the repeated one)

Verification / Alternative check:
Replacing the repeated 7 with 8 yields a clean alternating pattern: 5,16,6,16,7,16,8,16,9 — a neat, consistent design.

Why Other Options Are Wrong:
9 and 6 fit the expected progression; “None of these” is unnecessary since a single mismatch exists.

Common Pitfalls:
Judging the whole sequence without isolating the alternating streams; missing that 16 is a deliberate constant on even positions.

Final Answer:
7