text: playing card question? six playing cards are lying face down on a table.2 of them are kings, but you don't know which are the kings.you pick 2 at random and turn them face up. which is most likely: 1. there will be at least 1 king among the 2 cards or 2. there will be no king among the 2 cards the number of different ways you can pick a couple is 15 (c(6,2)in combinatory calculus) the number of different couples having a king is 6: k1 k2 k1 --- k2 --- --- k1 --- k2 k2 k1  so the probability to pick a king is 6/15 = 2/5  the same number you get if you consider the "worse case" (first pick not a king) and calculate the probability to pick one of the 2 kings among the 5 cards left.  so it does work. 2/5 is exactly 40%. thus the probability not to pick any king is the complementary: 100% - 40% = 60%