-- There are 10 marbles all together, in the bag.
-- 3 of them are blue, so the probability of pulling
a blue marble on the first draw is 3/10 .
-- After that, there are 9 total marbles in the bag.
-- 2 of them are blue, so the probability of drawing
a blue marble this time is 2/9 .
The probability of both of these things happening is
(3/10 x 2/9) = 6/90 = 1/15 = (6 and 2/3) percent.