Calculate the expected value of red marbles out of a bag containing 7 red marbles and 9 blue marbles if you are taking 5 marbles from the bag.
+130511 I assume you mean that all 5 marbles are red???....if so,
We have (7/16) chance of drawing a red marble on the first draw.......and, assuming that we draw a red one on the first draw, we have a (6/15) chance of a red one on the second draw, etc......so....the probability of all 5 being red is just :
(7/16) (6/15)(5/14)(4/13)(3/12) = 1/208 = about .0048 = about 0.48 %
+130511 I assume you mean that all 5 marbles are red???....if so,
We have (7/16) chance of drawing a red marble on the first draw.......and, assuming that we draw a red one on the first draw, we have a (6/15) chance of a red one on the second draw, etc......so....the probability of all 5 being red is just :
(7/16) (6/15)(5/14)(4/13)(3/12) = 1/208 = about .0048 = about 0.48 %
