Classification – Odd one out (unique multiple of 5) Inspect the four numbers below. Exactly one of them is a multiple of 5 (it ends with the digit 0 or 5). Identify that special case and mark it as the odd one out.

Introduction / Context:
When classifying numbers quickly, the simplest high-yield checks involve last-digit patterns and digit sums. Multiples of 5 always end with 0 or 5; this rule is instant to apply and often forms the basis of an odd-one-out decision when only one option exhibits that trait. Although deeper properties (like divisibility by 3) can also appear, the item is typically designed so that a single, unmistakable feature isolates the outlier.

Given Data / Assumptions:

• Options: 1593, 3781, 7359, 9175
• We are checking for a single multiple of 5.
• No hidden formats; ordinary base-10 integers.

Concept / Approach:
The multiple-of-5 test: a number is divisible by 5 if and only if its last digit is 0 or 5. Run this one-step test first. If it singles out exactly one member, you have the odd one out. If more than one passes, you would need a secondary property (e.g., divisibility by 3), but here only one will pass.

Step-by-Step Solution:
1593 → last digit 3 → not a multiple of 5.3781 → last digit 1 → not a multiple of 5.7359 → last digit 9 → not a multiple of 5.9175 → last digit 5 → multiple of 5 (indeed 5 * 1835).

Verification / Alternative check:
For completeness, you may also consider divisibility by 3 via digit sums: 1593 (sum 18) and 7359 (sum 24) are divisible by 3, while 3781 (sum 19) and 9175 (sum 22) are not. This secondary property produces two and two, so it does not give a unique odd element. In contrast, the multiple-of-5 rule isolates exactly one value (9175), which is the intended basis for classification here.

Why Other Options Are Wrong:

• 1593: Does not end in 0 or 5 → not a multiple of 5.
• 3781: Does not end in 0 or 5 → not a multiple of 5.
• 7359: Does not end in 0 or 5 → not a multiple of 5.
• None of these: A unique multiple of 5 exists (9175) → this distractor is incorrect.

Common Pitfalls:
Relying on even/odd status or digit-sum patterns without first checking the most decisive single-feature rule. Always apply the last-digit test for 5 and 10 early; it is faster and often conclusive.

Final Answer:
9175