SOLUTION: 3 green pens, 6 red pens, 12 bl pens, 9 violet pens... 7 pens r needed. and a bl and red pen have already been selected then the probability of obtaining at least 1 green pen is?

Algebra ->  Permutations -> SOLUTION: 3 green pens, 6 red pens, 12 bl pens, 9 violet pens... 7 pens r needed. and a bl and red pen have already been selected then the probability of obtaining at least 1 green pen is?      Log On


   



Question 372418: 3 green pens, 6 red pens, 12 bl pens, 9 violet pens... 7 pens r needed. and a bl and red pen have already been selected then the probability of obtaining at least 1 green pen is?
Answer by edjones(8007) About Me  (Show Source):
You can put this solution on YOUR website!
nCr=Combination of n things taken r at a time.
There is a total of 30 pens. Two have already been selected. 5 of 28 yet to be selected.
(3C0 * 25C5)/28C5
=53130/98280
=.5406 probability that no green pens will be obtained from a random drawing.
1-.5406=.4594 probability that at least 1 green pen will be obtained from a random drawing.
.
Ed