Answer: 4 people can be selected out of 8 people in 8C4 ways = 70 (total number of cases). Assuming that Andrew is among the 4 volunteers selected, we have 3 remaining spots for 6 candidates (as Karen can't be on the same team as Andrew we do not consider her as a candidate for the first team). Now, 3 people can be selected out of 6 candidates in 6C3 ways = 20 (favorable number of cases). Our required probability P = Favorable Number of Cases / Total Number of Cases = 20/70 = 2/7.