यदि (7) अलग पुस्तकों में से (3) पुस्तकों को शेल्फ पर क्रम में रखना है तो कौन-सी formula connection सही है?
If (3) books out of (7) distinct books are to be placed on a shelf in order then which formula connection is correct?
Explanation opens after your attempt
B. \(^{7}P_3\)
Concept
Both selection and order are needed so \(^{7}P_3=^{7}C_3\cdot3!\). In exams use permutation when order matters.
Why this answer is correct
The correct answer is B. \(^{7}P_3\). Both selection and order are needed so \(^{7}P_3=^{7}C_3\cdot3!\). In exams use permutation when order matters.
Exam Tip
पहले चयन और फिर क्रम दोनों चाहिए इसलिए \(^{7}P_3=^{7}C_3\cdot3!\)। परीक्षा में order matters हो तो permutation लें।
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