If two boys and a girl can beat their father in a tug-of-war, but their mother can win against a boy and two girls, who should win a contest between the father and a girl against the other and a boy?

If two boys and a girl can beat their father in a tug-of-war, but their mother can win against a boy and two girls, who should win a contest between the father and a girl against the other and a boy?