Jonas has 4 classical music CDs. 5 country music CDs, and 3 rock music CDs. In how many different ways can he arrange them so that the CDs of the same type are contiguous? Solution There are 4! ways to arrange the classical music CD\'s, 5! ways to arrange the country music CD\'s, and 3! ways to arrange the rock music CD\'s. Lastly, there are 3! ways to arrange the 3 genres of CD\'s. Therefore the answer is 4!5!3!3! = 24*120*6*6 = 103,680.