Q- Two cards are drawn in succession from a deck without replacement. What is the probability that both cards are greater than 2 and less than 8?
My solution:
probabilty = n/N
n = 5 x 4
N = 52 cards
probability = 20 / 52
BUT the answer is 95/663
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Q- Two cards are drawn in succession from a deck without replacement. What is the probability that both cards are greater than 2 and less than 8?
My solution:
probabilty = n/N
n = 5 x 4
N = 52 cards
probability = 20 / 52
BUT the answer is 95/663
you got the first step down.
there are 5 cards (per suit) that's between 2 - 8. (3, 4, 5, 6, and 7)
there are 4 suits.
so there are 20 cards out of 52 cards that you're looking for. That's for the FIRST pick.
20/52
second pick, you are left with 19 cards out of 51 cards.
19/51
(20/52)(19/51) = 95/663
That's a nice explanation given by I sneezefunny. You can also use combinations.
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