a group of professionals sit at a table at a conference. before the presentation begins, they all put their cellular phones (they each have 1) into a basket in the middle of the table. one of them, keira, has a white phone. assume that each of the remaining phones at the table (not belonging to keira) has a probability of being white, independent of each other. at the end of the presentation, keira reached for a phone in the basket before everyone else. given that the phone she picked is white, what is the probability that the phone in her hand is actually hers?