What was the question for this implicit rationale, and corresponding answer?
The number of males in the party was 2 males / 3 guests * 60 guests = 40 males. If the total number of people at the party was 60, then there were 60 guests - 40 males = 20 females.
 The answer: 20
The question: Princeton had a gender reveal party and invited all of his fellow employees to celebrate with him. If the total number of guests were 60, and 2/3 were male guests, how many female guests attended the party?