If I draw four cards from a deck of 52 cards, what is the probability that I will have one card of every suit?
First card: p1 = 1;
Second card p2 = 39/51
Third card p3 = 26/50
Fourth card p4 = 13/49
Overall probability = p1*p2*p3*p4
I'll leave you to do the number crunching.