For a certain​ candy, 20​% of the pieces are​ yellow, 5​% are​ red, 5​% are​ blue, ​15% are​ green, and the rest are brown. ​a) If you pick a piece at​ random, what is the probability that it is​ brown? it is yellow or​ blue? it is not​ green? it is​ striped? ​b) Assume you have an infinite supply of these candy pieces from which to draw. If you pick three pieces in a​ row, what is the probability that they are all​ brown? the third one is the first one that is​ red? none are​ yellow? at least one is​ green?