Classification – Ordered pairs (affine rule): pick the odd one out. In three pairs the mapping is y = 4x − 1; one pair violates this exact rule. Which pair is different? Options: 6 : 23, 3 : 11, 1 : 3, 5 : 18.

Introduction / Context:
Affine mappings of the form y = ax + b are common in number-pair classifications. Verifying a single rule across several pairs reveals the exception cleanly.

Given Data / Assumptions:

• Candidate rule: y = 4x − 1.
• Pairs: (6,23), (3,11), (1,3), (5,18).

Concept / Approach:
Plug each x into y = 4x − 1 and compare the computed result with the given y.

Step-by-Step Solution:
x=6 → 24−1=23 → matches.x=3 → 12−1=11 → matches.x=1 → 4−1=3 → matches.x=5 → 20−1=19 ≠ 18 → violation.

Verification / Alternative check:
Invert the rule: from y compute (y+1)/4; for y=18 this gives 19/4=4.75, not integer, confirming the mismatch.

Why Other Options Are Wrong:
6:23, 3:11, 1:3: Each satisfies y = 4x − 1 exactly.

Common Pitfalls:
Assuming a different slope or constant that cannot fit all three compliant pairs simultaneously.

Final Answer:
5 : 18