Tom keeps all of his favorite marbles in a special leather bag. right know five red marbles four marbles and three marbles are in the bag .
part a: if he randomly chooses one marbles to give to a friend what is the probability that it is blue.

part b: tom does not really want to give away blue marbles and would like to change the probability that he choose a blue marble to 1/10. how many marbles that are not blue could he add to the bag so that the probability of choosing a blue marble becomes 1/10