Four friends have each ordered a different textbook. When they arrive in the same package, they are distributed at random, one book to each person. Everyone who got their correct textbook leaves happily. Among the people who remain, their textbooks are re-distributed at random again.
(a) What is the probability that Jenn ordered the Introduction to Counting textbook?
(b) What is the probability that Jenn ordered the Introduction to Counting textbook and Glenn ordered the Introduction to Number Theory textbook?
(c) What is the probability that Jenn ordered the Introduction to Counting textbook and Glenn ordered the Introduction to Number Theory textbook and Paul ordered the Introduction to Algebra textbook?
(d) What is the probability that Jenn gets the correct textook after the first round?
(e) What is the probability that Jenn and Glenn gets the correct textook after the first round?
(f) What is the probability that Jenn and Glenn and Paul gets the correct textook after the first round?
(g) What is the probability that Jenn gets the correct textook after the second round?
(h) What is the probability that Jenn and Glenn gets the correct textook after the second round?
(i) What is the probability that Jenn and Glenn and Paul gets the correct textook after the second round?
