Adeck of cards has 3 blue, 4 black, and 6 purple cards. draw 2 cards without replacing any cards. what is the probability of both cards being blue?

To solve this question, simply add up the total number of cards in the pile

This is 11 cards remove 2 so this is 9.

The probability of 1 card being blue is 3/9 or 1/3.

Both would be (1/3)^2 which is 1/9.

1/26

The probability of the first card being blue is 3/13, black is 4/13, and purple is 6/13. Presuming that the first card will be blue, and is then removed, then the odds now stand at 2/12 for blue (there is one less blue, and one less card, so both numbers decrease), 4/12 for black (the number of black remains the same but a different card has been removed, so only the bottom number changes) and 6/12 for purple (explanation as with black).
So, the odds are 3/13 and 2/12 that both cards will be blue. Multiplying these together gives your final answer of 3/78, or 1/26!

Hope this helped you! It was hard to explain, so if you need clarification, just say.