Amanda has a box of identically sized hair ties: 14 are black, 8 are red, 20 are brown, and 6 are blue.
a) If Amanda grabs a hair tie, puts it back, and then grabs another, what is the probability that she would grab a black hair tie followed by a blue hair tie?
b) If Amanda grabs a hair tie, keeps it, and then grabs another, what is the probability that she would grab a red hair tie followed by brown hair tie?