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There are 4 copies of Statistics book, 5 copies of Science book,
and 3 copies of English book. In how many ways can they be arranged on a shelf?
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Based on context, I interpret the given part as if the copies of each kind are undistinguishable.
Then the question is: how many DISTINGUISHABLE arrangements are there in this situation ?
The total number of books is 4+5+3 = 12; the multiplicities are 4, 5 and 3.
Use the formula for the number of distinguishable arrangements and get the number
= = 27720.
ANSWER. The number of distinguishable arrangements is 27720.
Solved.
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To see many other similar (and different) solved problems, look into the lesson
- Arranging elements of sets containing indistinguishable elements
in this site.
Also, you have this free of charge online textbook in ALGEBRA-II in this site
- ALGEBRA-II - YOUR ONLINE TEXTBOOK.
The referred lesson is the part of this online textbook under the topic "Combinatorics: Combinations and permutations".
Save the link to this textbook together with its description
Free of charge online textbook in ALGEBRA-II
https://www.algebra.com/algebra/homework/complex/ALGEBRA-II-YOUR-ONLINE-TEXTBOOK.lesson
into your archive and use when it is needed.