Analogy (numbers) — “17 : 34 :: ? : 10”. Use the same operation to find the missing number.

Introduction / Context:
The mapping 17 → 34 doubles the number. Apply the same operation to get a number that maps to 10.

Given Data / Assumptions:

• Rule: x → 2x.
• We want y such that 2y = 10.

Concept / Approach:
Solve for y = 10 / 2.

Step-by-Step Solution:

Verification / Alternative check:
Check the stem: 17 × 2 = 34; thus symmetry holds.

Why Other Options Are Wrong:
Only 5 doubles exactly to 10.

Common Pitfalls:
Assuming addition when the stem suggests multiplication.

Final Answer:
5