Question

A deck of cards are shuffled 20 times. You are dealt 12 cards at random:
what is the probability that all 12 cards are black? or
what is the probability that all 12 cards are kings, queens or jacks

Answer 1

first one black = 26/52 = 1/2
second one black = 25/51
third one black = 24/50
fourth one black = 23/49
etc until we get to number 12
then multiply all those fractions

that means you got every king, queen and jack
4 kings + 4 queens + 4 jacks = 12 of the 52

card 1 = 12/52
card 2 = 11/51
card 3 = 10/50
etc down to card 12
then multiply
king 3 = 10/50
king 4 =