अंकों (0,1,2,3,4,5,6,7) से बिना पुनरावृत्ति (5) अंकों की कितनी संख्याएं बनेंगी जो (5) से विभाज्य हों?
How many (5)-digit numbers divisible by (5) can be formed from (0,1,2,3,4,5,6,7) without repetition?
Explanation opens after your attempt
B. (1260)
Concept
The last digit is (0) or (5), and both cases must be counted separately. The total is \(^{7}P_4+6\cdot{}^{6}P_3=840+420=1260\).
Why this answer is correct
The correct answer is B. (1260). The last digit is (0) or (5), and both cases must be counted separately. The total is \(^{7}P_4+6\cdot{}^{6}P_3=840+420=1260\).
Exam Tip
अंतिम अंक (0) या (5) होगा और दोनों cases अलग-अलग गिनने होंगे। कुल \(^{7}P_4+6\cdot{}^{6}P_3=840+420=1260\) है।
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