Let, Michael and Anthony be considered as a single unit. Then we have to select 1 person from remaining 4 to form a 3 member subcommitee.
1 person can be selected in 4C1 =4 ways.
Now, according to question, 2 subcommitees are to be formed, so total ways = 4*2 = 8

Total no of ways of selecting 3 people from 6 = 6C3=20
Percentage = 8/20 = 40%

jimmiejaz wrote:Let, Michael and Anthony be considered as a single unit. Then we have to select 1 person from remaining 4 to form a 3 member subcommitee.
1 person can be selected in 4C1 =4 ways.
Now, according to question, 2 subcommitees are to be formed, so total ways = 4*2 = 8

Total no of ways of selecting 3 people from 6 = 6C3=20
Percentage = 8/20 = 40%

Beautiful.

what percent of all the possible subcommittees that include Michael also include Anthony?

Total number of 3 member committees that include Michael:
5C2 = 10 (with Michael as the third member)

Total number of 3 member committees that include Michael and Anthony:
4C1 = 4 (with Michael and Anthony as the two members)

now 4 is what percent of 10? = 40%

jimmiejaz, logitech

Could you please explain this step:-

Now, according to question, 2 subcommitees are to be formed, so total ways = 4*2 = 8

Question - Why did you do this ? Once you have Michael and Anthony together, there are just 4 different ways in which 2 subcommitees could be formed. Why multiply by 2 ? The second subcommittee is formed automatically once you have chose the third person who would be with Anthony and Michael.