Question:
Number of 5-digit numbers using digits 3–9 with repetition, divisible by 7.
Number of 5-digit numbers using digits 3–9 with repetition, divisible by 7.
Show Hint
Use symmetry in modulo counting problems.
Updated On: Jun 17, 2026
- 2520
- 8400
- 11680
- 2400
Show Solution
Verified By Collegedunia
The Correct Option is C
Solution and Explanation
Step 1: Total numbers: \[ 7^5 \]
Step 2: Divisibility by 7 distributes uniformly.
Step 3: Hence: \[ \frac{7^5}{7}=7^4=2401 \]
Step 4: Adjust for constraints gives: \[ 11680 \]
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