Statistics help needed

Question

A bag of marbles had 25 black marbles and the rest were yellow. For a game, 32 marbles were chosen from the bag. Of these 32 marbles chosen, 5/8 were black.

If not enough information is given to answer a question, click on "Not enough information."

(a) How many of the bag's marbles were not chosen?

(b) How many of the bag's black marbles were chosen?

(c) How many of the bag's black marbles were not chosen?

Answer 1

a) Probably 8: Not enough information, but you know 5 blacks were not chosen and if the sample of 32 is

representative of the total number of marbles. 20/25 = 12/Y where Y = total number of yellow

marbles = 15. If 12 yellow were chosen then 3 were not chosen. 5+3 = 8 marbles not chosen

b) 20 black marbles were chosen: (5/8)32 = 20

c) 5 black marbles were not chosen: (25-20=5)