You have 8 teams. They will be drawn one against each other, so 4 pairs in total.

Question 1: how many distinct pair sets are possible?

105. I got to this number after running a large number of simulations. Then I did a little bit of research and I also found the formula:

Question 2: if 4 of the 8 teams are from England, what is the probability that all 4 of them will be drawn together?

Again, after analyzing the 105 distinct pair sets, I found that only 9 of them have all-English pairs. The full probability set is:

• two English pairs: 9/105 or 8.57%
• exactly one English pair: 72/105 or 68.57%
• no English pair: 24/105 or 22.86%

CL draws probabilities – follow up for the quarterfinals:
8.57% – 2 English QF
68.57% – exactly 1 English QF
22.86% – no English QF

cc @emi_nga @julienguyon1977 @iamsircolin @BassTunedToRed @joel_archie @paul_tomkins @DanKennett

— Dorin M. (@dorinmoise) March 14, 2019