posted by Michelle .
Bert has a bag with 12 blue marbles, 6 green marbles, 8 purple marbles, and 4 red marbles. If he want the probability of picking a blue marble to be 1/2 what should he do?
Right now the probability of picking blue would be 12/30. If you add another blue it would be 13/31, then 14/32, 15/33, 16/34, 17/35, 18/36. 18/36=1/2, so if he wants the probability to be 1/2 he needs to add 6 more blue.