Answer Happy

3. Suppose that an urn contains 4 red balls, 5 blue balls, and 6
green balls.
(a) What is the probability that, when randomly drawing out
three balls from the urn without replacement, you draw one ball of
each color?
(b)What is the probability that, when randomly drawing out three
balls from the urn without replacement, you draw three balls of the
same color?
(c) Suppose you were randomly drawing balls from the urn
one-by-one without replacement. What is the probability that you
need to draw out at least four balls before you draw the first
green ball?
(d) Repeat the previous problem, but now assume that you draw
the balls WITH replacement.