Logic Riddles

Question: A young woman is attending her mother's funeral. While there, she meets a man she has never seen before and falls in love immediately. After the funeral she tries to find him but cannot. Several days later she kills her sister.

Why does she kill her sister?

Question: In 1940, a correspondent proposed the following question:

A man's age at death was one twenty-ninth of the year of his birth. How old was he in 1900?

Question: I'm number three.
But I'm not a number.
I'm hot and cold at the same moment but not at the same time.
I'm number three.
But I'm not a number.

Who or what am I?

Question: Mr. Smith has two children. If the older child is a boy, what are the odds that the other child is also a boy?

Question: You are surrounded by a 100 foot wide and 100 foot deep moat. You have a 40 foot tall ladder, matches, a gallon of water, and as much rope as you need.

How can you get across the moat?