Its a general aptitude exam question that i faced in one of my interviews:

Two twins have certain peculiar characteristics. One of them always lies on Monday, Wednesday, and Friday. The other always lies on Tuesdays, Thursdays and Saturdays. On the other days they tell the truth.

You are given a conversation.

Person A-- today is Sunday my name is Anil
Person B -- today is Tuesday, my name is Bill
What day is today?

Ans: Today is Tuesday

any explanation for this answer?