There are two dogs, a black one and a white one. One is male. What is the probability they are both male?

You and your spouse invite four other couples to a party. During the course of the conversation, it is discovered that, prior to the party, each person except you was acquainted with a different number of the people present. Assuming the acquaintance relationship is symmetric (i.e., if you are acquainted with someone, that person is also acquainted with you), then how many people did your spouse know prior to the party? How many people did you...

There were three creatures outside a building. One of the creatures did not move itself but entered the building and knew that it was in the building. The second creature moved itself, entered the building, and knew that it was in the building. The last creature did not move itself but entered the building, and the creature did not know that it was in the building. What are the three creatures?

The winner of the World Series is the first team to win four games, so the maximum number of games that could be played is 7. You want to place a $100 bet (even money) on your team to win the whole series. A bookie says he will not take bets on the whole series, but would be willing to let you bet on each individual game. Is there a betting strategy you could put in place to replicate your $100 bet?

Fred and Ethel go to the golf course. They meet 3 other couples there, and everybody gets introduced. After introductions, Fred asks everyone how many hands they shook. He gets seven different answers. Presume that no one shook their partner's hand

How many hands did Ethel shake?

What's the secret to the sequence? What's the next number?

4, 5, 9, 11, 12, 13, 14...