अंकों (1,2,3,4,5,6,7,8,9) से (5) अंकों की कितनी संख्याएँ बनेंगी जिनमें अंक दोहराए न जाएँ और संख्या (9) से विभाज्य हो?
Using digits (1,2,3,4,5,6,7,8,9), how many (5)-digit numbers can be formed without repetition and divisible by (9)?
Explanation opens after your attempt
Correct Answer
C. (1680)
Concept
First choose (5)-digit sets whose sum is divisible by (9), then arrange each set in (5!) ways. Start divisibility problems with the digit sum.
Why this answer is correct
The correct answer is C. (1680). First choose (5)-digit sets whose sum is divisible by (9), then arrange each set in (5!) ways. Start divisibility problems with the digit sum.
Exam Tip
पहले ऐसे (5) अंकों के समूह चुनें जिनका योग (9) से विभाज्य हो, फिर (5!) क्रम लगाएँ। विभाज्यता के प्रश्न में अंकों के योग से शुरुआत करें।
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