yashaswikhandelia
Can you please explain how 1 is sufficient? There can be 11 members in A, 11 members in B. There can be 2 people who are members of neither A or B. Or these 11 members can be the same who are part of both A & B
If both club A and club B have more than 10 members each, are there some people who are members of both club A and club B?(1) All those who are not members of club A, are also not members of club B.
This means anyone in club B must also be in club A because if a person were in club B but not in club A, then that person would be a counterexample to the statement. Since such a person cannot exist, all members of B must also be in A. So every member of B is also in A. Since club B has more than 10 members, at least those 10+ people are definitely in both clubs. Sufficient.
(2) All those who are members of club B, are also members of club A.
This says the same thing: anyone in B must also be in A because if someone belonged to club B without belonging to club A, the condition would be violated. Therefore every member of B must already be a member of A. So again, every member of B is in both clubs. Since B has more than 10 members, there are definitely people in both. Sufficient.
Answer: D.