If 5 cats catch 5 mice in 5 minutes, how long will it take one cat to catch a mouse?

Christina has four daughters, and each of her daughters has a brother. How many children does Christina have?

Three people enter a room and have a green or blue hat placed on their heads. They cannot see their own hat but can see the other hats.
The colour of each hat is purely random. They could all be green, blue, or any combination of green and blue.
They need to guess their own hat colour by writing it on a piece of paper, or they can write 'pass'.
They cannot communicate with each other in any way once the game starts. But they can have a strategy meeting before the game.
If at least one of them guesses correctly they win $10,000 each, but if anyone guesses incorrectly they all get nothing.
What is the best strategy?

what does the below rebus mean?

I am an odd number. Take away a letter and I become even. What number am I?

I have branches, but no fruit, trunk or leaves. What am I?

A man who was outside in the rain without an umbrella or hat didn’t get a single hair on his head wet. Why?

I am eight letters long - "12345678"
My 1234 is an atmospheric condition.
My 34567 supports a plant.
My 4567 is too appropriate.
My 45 is a friendly thank-you.
My 678 is a man's name.

What word am I?

An explorer goes on an exposition in the jungle. He sets up camp in the middle of the jungle. The next morning he sees something with a head and a tail, but he is not afraid. What did he see in his bag?

Why is the Hole below a Lock?