Thursday, May 20, 2010

What is the probability of drawing a spade or a picture card from a regular deck of playing cards? plz help?

If this is one question: P(spade OR Face Card) in one draw:





There are 13 unique spades in a deck of 52 cards


Each suit has 3 Face cards, therefore there are 12 Face cards


However, 3 of them are already spades, so you don't want to double count those.





Therefore, there are 13 spades and 9 non-spade Face Cards.





Your probability is then: (13+9)/52 = 22/52 or 11/26 = 42.3% chance

What is the probability of drawing a spade or a picture card from a regular deck of playing cards? plz help?
use P(a) + P(b) - P(a intersection b) ----i used the word intersection instead of the symbol, inverted U)





P(a) = 13 cards(spades)


P(b) = 12 picture cards(K,Q and J; 4 each)


P(a intersection b) = 3( K of spades, Q of spades and J of spades)





that is 13/52 + 12/52 - 3/52 = 22/52 = 11/26
Reply:spade is 1/4


picture card is 9/52








we have 13 spades, and 9 picture cards. But 3 of the picture cards are spades, so we have


13+9-3


---------


52





or 19/52 or 0.365
Reply:How many cards out of 52 are either spades or picture cards? The probability is that number over 52.
Reply:s = spade


c = picture card





p(s or c) = p(s) + p(c) - p(s and c)


= 13/52 + (4*3)/52 - 3/52 = (13 + 12 - 3)/52 = 22/52


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