अंकों (1,2,3,4,5,6,7,8) से बिना पुनरावृत्ति कितनी (4)-अंकीय संख्याएं (4000) से बड़ी बनेंगी?
How many (4)-digit numbers greater than (4000) can be formed from (1,2,3,4,5,6,7,8) without repetition?
Explanation opens after your attempt
A. (840)
Concept
The thousands digit can be (4,5,6,7,8), and the remaining (3) places are filled in \(^{7}P_{3}\) ways. In comparison questions, fix the first digit first.
Why this answer is correct
The correct answer is A. (840). The thousands digit can be (4,5,6,7,8), and the remaining (3) places are filled in \(^{7}P_{3}\) ways. In comparison questions, fix the first digit first.
Exam Tip
हजार का अंक (4,5,6,7,8) में से होगा और बाकी (3) स्थान \(^{7}P_{3}\) तरीकों से भरेंगे। तुलना वाले प्रश्नों में पहले पहला अंक तय करें।
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