Probability question: What is the probability that four cards are randomly selected from a deck of 52 cards, and at least two of these four cards are spades?

There are at least two spades, namely two spades, three spades and four spades.

P (2) = c (13,2) * c (52-13,2)/c (52,4) = 4446/20825.

P (three sheets) = c (13,3) * c (52-13,1)/c (52,4) = 858/20825.

P (four sheets) = c (13,4)/c (52,4) =11/4165.

P (total) = 5359/20825 = 0.30000005