if 2 sets A and B are having 99 elements in common ,then the number of elements common to each of the sets A*B AND B*A ARE

if 2 sets A and B are having 99 elements in common ,then the number of elements common to each of the sets A*B AND B*A would be 99 X 99 as you can choose 99 elements which are common to both A and B in 99 ways separately in both the sets and when you will multiply these, you will get the same answer.