As a fraction in simplest form, what is the probability of drawing a queen or black card from a standard deck of playing cards?

Answer 1

P(Q) = 4/52 = 1/13 One out of 13 cards are queens

P(B) = P(Spade vClub) = 26/52 = 1/2 Half the deck are black cards

P(Q v B) = P(Q) + P(B) - P(Q^B)

= 1/13 + 1/2 - P(Q^B) = 2/26 +13/26 - 1/26 = 14/26 = 7/13 = about 53.85%

= about 54% chance of a queen or a black card

P(QvB) = 7/13 in simplest fraction form