A group of 6 books consists of 2 identical books on mathematics, 2 identical books on science, and 2 identical books on literature. In how many different ways can you arrange the books on a shelf if the books of the same subject must be kept together?
5
8
3
4
To calculate the number of different ways the group of 6 books can be arranged on a shelf, with the books of the same subject kept together, we can treat each subject group as a single entity.
Since there are 3 subject groups (mathematics, science, and literature), we need to arrange these 3 entities on the shelf.
The number of ways to arrange the mathematics books among themselves is given by , the number of ways to arrange the science books among themselves is given by
, and the number of ways to arrange the literature books among themselves is given by
Therefore, the total number of different ways to arrange the books on the shelf, with the books of the same subject kept together, is:
Therefore, there are 8 different ways the group of 6 books can be arranged on the shelf, keeping the books of the same subject together.
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