There are 7 different large books, 5 equal medium ones and 3 equal small ones. In different ways can they be lined up on a shelf if the same sizes are to be placed together?

Answer 1

The 3 small books can be arranged in 3! ways
the 5 medium ..... 5! ways
the 7 large ..... 7!

Besides that, the 3 groupings of books, small - medium - large, can
also be arranged in 3! ways

Number of arrangements as stated = 3! * 3! * 5! * 7!