non routine problem

Question

A woman, her brother, her son, and her daughter (all relatives by birth) are tennis players. The worst player's twin (who is one of the four players) and the best player are of the opposite sex. The worst player and the best player are the same age. Who is the worst player?

the woman
her son
her brother
her daughter

Answer 1

Either the woman and her brother can be twins or the brother can be much younger than the woman and be the same age as the son and the daughter (who are twins). Obviously, the woman can not be the same age as her children.

 

The worst player's twin and the best player are the opposite sex, so the worst player and the best player are the same sex. Since the woman and the daughter cannot be the same age, the best and worst player must be the men (the brother and the son). The worst player is one of the twins, so the answer is the son.