There are 52 cards in a deck. If you draw a card and don't replace it, there are only 51 cards left
a) There are 13 spades and 13 clubs
P(spade or club) = (13+13)/52 = 26/52 = 1/2 = 0.5
b) There are 13 diamonds and 4 queens; but one is the Q of diamonds which we've already counted. So there are only three additional queens:
P(diamond or queen) = (13 + 3)/52 = 16/52 = 4/13 ≈ 0.308
c) Here we draw two cards, a spade then a club:
P(spade and club) = 13/52 * 13/51 = 169/2652 ≈ 0.064
d) There are 4 twos in the deck. If you pick one and don't replace it, there are only 3 twos left (and 51 cards):
P(two and two) = 4/52 * 3/51 = 1/221 ≈ 0.0045
