Roll dice and flip coin:
Probability of rolling a cube and getting a 3 = 1/6 .
Probability of flipping a coin and getting HEADS = 1/2 .
Probability of both = (1/6) x (1/2) .
You do the multiplication.
4 blue, 2 green, 6 red
Probability of a blue on the first draw = 4 out of 12 marbles = 1/3 .
Without putting the blue back in ...
Probability of a red on the next draw = 6 out of 11 marbles = 6/11 .
Probability of both = (1/3) x (6/11) .
You do the multiplication.