(7) अलग-अलग पुस्तकों को शेल्फ पर कितने तरीकों से रखा जाए ताकि दो विशेष पुस्तकें न तो साथ हों और न ही दोनों सिरों पर हों?
In how many ways can (7) distinct books be arranged on a shelf so that two particular books are neither together nor both at the ends?
Explanation opens after your attempt
Correct Answer
B. (3720)
Concept
Subtract together cases \(6!\cdot2!\) and both-end cases \(2!\cdot5!\) from (7!). There is no overlap because both-end positions are not together, so the result is (5040-1440-240=3360).
Why this answer is correct
The correct answer is B. (3720). Subtract together cases \(6!\cdot2!\) and both-end cases \(2!\cdot5!\) from (7!). There is no overlap because both-end positions are not together, so the result is (5040-1440-240=3360).
Exam Tip
कुल (7!) से साथ वाली \(6!\cdot2!\) और दोनों सिरों वाली \(2!\cdot5!\) व्यवस्थाएं घटाएं। overlap साथ नहीं हो सकता, इसलिए (5040-1440-240=3360) मिलता है।
Login to save your score, XP, coins and progress.