A card is drawn at random from a well-shuffled deck of playing cards. Find the probability that the card drawn is (i) a card of spades or an ace, (ii) a red king, (iii) either a king a queen, (iv) neither a king nor a queen.

Total numbers of elementary events are: 52

(i) Let E be the event of drawing a card of spade or an ace


Let A be the event of drawing a card of spade


The favourable numbers of drawing a card of spade are: 13


P (spade) = P (E) = 13/52


Let B be the event of drawing an ace


The numbers of favourable outcomes are: 3 one ace being spade card already been counted


P (ace) = P (B) = 3/52


P (spade or ace) = P (E) = P (A) + P(B) = 13/52 + 3/52 = 16/52 = 8/26 =4/13


(ii) Let E be the event of drawing a red king


The numbers of favourable outcomes are: 2


P (red king) = P (E) = 2/52 = 1/26


(iii) Let E be the event of drawing either a king or a queen


Let A be the event of drawing a king


Then, the numbers of favourable outcome are: 4


P (king) = P (A) = 4/52


Let B be the event of drawing a queen


Then, the numbers of favourable outcome are: 4


P (queen) = P (B) = 4/52


P (king or queen) = 4/52 + 4/52 = 8/52 = 2/13 -----@


(iv) Let E be the event of drawing neither a king nor a queen


P (getting either king or a queen) = 2/13 (part c above ----@)


P (neither king nor queen) = P (E) = 1 – P (either king or queen) = 1 – 2/13 = 11/13


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