अंकों (1,2,3,4,5,6,7,8,9) से बिना पुनरावृत्ति (4) अंकों की कितनी संख्याएं (4000) और (8000) के बीच होंगी?
How many (4)-digit numbers between (4000) and (8000) can be formed from (1,2,3,4,5,6,7,8,9) without repetition?
Explanation opens after your attempt
B. (1680)
Concept
The thousands place has (4) choices from (4,5,6,7), and the remaining places have \(8\cdot7\cdot6\) ways. The total is (1344).
Why this answer is correct
The correct answer is B. (1680). The thousands place has (4) choices from (4,5,6,7), and the remaining places have \(8\cdot7\cdot6\) ways. The total is (1344).
Exam Tip
हजार स्थान पर (4,5,6,7) में से (4) विकल्प हैं और बाकी \(8\cdot7\cdot6\) तरीके हैं। कुल (1344) है।
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