Permutations & Combinations
3-digit Numbers Divisible by 6 with Repetition
nta_pyq_2023_apr
Grade 11
Question:
Total 3-digit numbers divisible by 6, using $\{1,2,3,4,5\}$ with repetition, is ________
Step-by-Step Solution
Key Concept: Divisible by 6: divisible by both 2 and 3. Divisible by 2: last digit even $\in\{2,4\}$. Divisible by 3: digit sum divisible by 3.
16 numbers.
Correct Answer: 16