Abag contains 9 blue marbles and 3 red marbles. you draw three marbles without replacement. what is the probability of drawing three blue marbles? 21⁄55 = 38.2% 6⁄11 = 54.5% 7⁄24 = 29.2% 56⁄81 = 69.1% 243⁄440 = 55.2%

Let's see what's happening with each extraction, in terms of favourable cases vs total cases:

With the first extractions, you have 12 marbles, and 9 of them are blue. The probability of extracting a blue one is thus

.

With the second extractions, you have 11 marbles (we don't replace the first one!), and 8 of them are blue (we already picked one!). The probability of extracting a blue one is thus

.

Finally, you have 10 marbles, and 7 of them are blue (we already picked two!). The probability of extracting a blue one is thus

.

If you want events to happen one after the other, you have to multiply their probabilities, so the answer is

good luck!

cutie~