3.109: Arrangements and letter selections
(a)[2]
3 men and 3 women are standing in a line. The 3 men are standing next to each other. Find how many different arrangements are possible.
(b)[3]
In the 13-letter word MULTIBRANCHED, there are 4 vowels, U, I, A and E. 7 different letters are selected from these 13 letters. Find how many different selections are possible if the selection includes at least 2 vowels.