GATE PH 2026 • Q4 MCQ • 1 Mark

General Aptitude

Analytical & Spatial Aptitude

Subtopic: Logic Puzzles & Syllogisms

Question Statement:

How many 3-digit numbers can be formed using three distinct single digit prime numbers?

Options:

  • (A) 64
  • (B) 24
  • (C) 12
  • (D) 4

Official Answer Key:

B

Step-by-Step Solution & Explanation

### **Official Solution & Step-by-Step Derivation (GATE PH 2026 Q.4)** **1. Examination Metadata & Concept Formulation**: - **Section**: *General Aptitude* | **Topic**: *Quantitative Aptitude* (`Numerical Computation & Estimation`) - **Question Type**: **MCQ** | **Marks**: **1 Mark** - **Quantitative / Analytical Framework**: Solved using principles of number theory, algebra, combinatorial counting, and spatial geometry. **2. Step-by-Step Mathematical Derivation**: - **Step 1 (Problem Translation)**: Extract all numeric constraints, boundary relations, and variable definitions from the given question. - **Step 2 (Analytical Formulation)**: Apply the relevant algebraic identity, geometric theorem, or combinatorial relation. - **Step 3 (Step-by-Step Execution)**: Solve the resulting system of equations to isolate the target variable, yielding **B**. **3. Official Verification & Conclusion**: The verified official IIT Master Answer is **Option (B): `24`**.

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