Consider again a standard deck of 52 cards (13 in each of 4 suits). Two cards are dealt in succession (meaning no replacement). What is the probability that both cards are greater than 7 (assuming that the ace is considered “high” or greater than 7)?

Question

amistre64 · Answer

how many cards are greater than a 7 in the deck?

anonymous · Answer

28, 4 sets of 8,9,10,J,Q,K,A. I know the probability for the first card is 28/52. I'm mainly confused about the second card. I know it will be x/51, but x could be either 28 or 27 depending on whether or not the first card was greater than 7. Or am I just looking at this wrong somehow?

amistre64 · Answer

assuming that the first card pulled is greater in the set of 28, that leaves 27 out of 51 left for the second pull

amistre64 · Answer

*is in the set of 28 ... had some competing ways to descibe it lol

amistre64 · Answer

in other words:

P(a) * P(b) is the probability of the result of both (a) and (b) happening.

28/52  is the probability of the first pull
27/51 is the probability of the second pull; given that the first one happened.

amistre64 · Answer

your over thinking it i believe.  the only way we can get the results if IF the P(a) happens; so this is just an offshoot of P(a) happening.

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