(9) people को line में arrange करना है और (A) तथा (B) together न हों। Count कौन-सी है?
(9) people are arranged in a line and (A) and (B) are not together. Which count is correct?
Explanation opens after your attempt
A. \(9!-8!\cdot2!\)
Concept
Subtract the arrangements where (A) and (B) are together as a block from total arrangements. In exams use complement for not together.
Why this answer is correct
The correct answer is A. \(9!-8!\cdot2!\). Subtract the arrangements where (A) and (B) are together as a block from total arrangements. In exams use complement for not together.
Exam Tip
Total arrangements से (A) और (B) together block arrangements घटते हैं। परीक्षा में not together को complement से करना आसान है।
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