Difficulty: Easy
Correct Answer: 20
Explanation:
Problem restatement
Form 3-digit numbers from {2, 3, 5, 6, 7, 9} that are divisible by 5 and have no repeated digits.
Given data
Concept/Approach
Fix the units digit as 5, then choose hundreds and tens from remaining distinct digits.
Step-by-step calculation
Units digit = 5 (1 way) Hundreds digit = choose from {2, 3, 6, 7, 9} ⇒ 5 ways Tens digit = choose from remaining 4 digits ⇒ 4 ways Total numbers = 1 × 5 × 4 = 20
Verification/Alternative
Listing logic shows structure H–T–5; choices reduce sequentially without repetition.
Final Answer
20
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