Answer the following questions about probability and countings. (a) There are 17 students in a class: 7 boys and 10 girls. If the teacher picks a group of 4 at random, what is the probability that everyone in the group is a girl? (b) Bart has six books: a novel, a biography, a dictionary, a self-help book, a statistics textbook, and a comic book. Bart chooses three books at random. What is the probability that the three books he chooses are statistics textbook, dictionary, and comic book, in that order?