Problem
COM-B1-M02-P009 Books by Subject
#9
★★☆☆☆ Level 2 of 5
On a shelf there are \(3\) math books, \(2\) physics books, and \(2\) history books, all distinct. In how many ways can they be arranged so that books of each subject stand together?
Treat each subject as a block.
The three subject blocks can be arranged in \(3!\) ways. Inside the blocks: \(3!\), \(2!\), \(2!\). Total: \(3!\cdot3!\cdot2!\cdot2!=144\).
Several blocks at once.