Question

An organization has 3 committees, only 2 persons are members of all 3 committee but every pair of committee has 3 members in common. what is the least possible number of members on any one committee?

Answer 1

the least possible no of member of members on any one committee = 4

In all 3 committees, say X,Y,Z, 2 persons say A and B are common.
C is common between X and Y.
D is common between Y and Z.
E is common between X and Z.

so X committee has ABCE. Y committee has ABCD. Z committee has ABDE.