Question 878670: in how many ways 5 physics,3 chemistry,3 maths books be arranged keeping book of same subject together
Answer by jim_thompson5910(35256)   (Show Source):
You can put this solution on YOUR website! Group the books by subject. You have 3 groups. So think of these 3 groups as 3 books (bind them up with tape or something)
There are 3! = 3*2*1 = 6 ways to arrange these 3 "books".
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Within the physics subgroup, there are 5! = 5*4*3*2*1 = 120 ways to arrange this set of books.
In the chem subgroup, there are 3! = 6 ways to arrange these books.
In the math subgroup, there are 3! = 6 ways to arrange these books.
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Multiply out the combos: 6*120*6*6 = 25,920
There are 25,920 total ways to arrange the books keeping them together in the same subject.
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