Three marbles are drawn without replacement from an urn containing 4 red marbles, five what marbles, and two blue marbles. Determine the probability that None is red

Answer 1

4 red out of (4+5+2)=11 marbles
Probability that first draw has no red
=(11-4)/11
=7

No replacement, so probability for second draw
= (10-4)/10
=6/10

Probability that both have no red
= product of the two probabilities.