Three cards from a standard deck are dealt. What is the probability that the first is a heart, the second is a spade, and the third is another heart?
The probability is 1/4*1/4*3/50 = 3/800.
1/4 * 13/51 * 12/50=13/850
1/4 is for 13 hearts out of 52 cards, then you have already chosen a card so you have 51 - but still 13 choices of spades, so 13/51
finally, you have 50 cards after picking 2, and you have 13-1=12 hearts available.