Analogy (numbers) — “4 : 9 :: 8 : ?”. Identify the pattern and complete the pair.

Introduction / Context:
A common simple-number analogy applies a constant increment: 4 → 9 is +5. Apply the same increment to 8 to get the missing term.

Given Data / Assumptions:

• Treat the mapping as A → A + k for a fixed k.
• Here, k = 5.

Concept / Approach:
Compute 8 + 5.

Step-by-Step Solution:

Verification / Alternative check:
Competing patterns (squares, etc.) are possible, but the minimal consistent rule here is a simple +5 shift for both pairs.

Why Other Options Are Wrong:
They do not equal 8 + 5.

Common Pitfalls:
Overcomplicating with non-linear transforms when a constant difference suffices.

Final Answer:
13