2. John watches a sequence of 8 pairwise distinct movies,

and he either likes or doesn't like each movie (assume

this is binary) with equal probability. What is the

probability of each of the following events?

(a) John likes exactly one of the first 3 movies.

(b) John likes all of the first 3 movies or the last 3

movies (note that this includes the case where John likes

both the first 3 and last 3 movies)