Can you find out the number that should replace the question mark with a valid reason?

What country can make you shiver?

Mr Red Lives in the red house.
Mr Green Lives in the greenhouse.
Mr Yellow Lives in the yellow house.

Who lives in the Whitehouse?

What does this mean?

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The person who makes it has no need for it. He who purchases it does not use it. The person who does use it does not know they are. What is it?

Can you count the number of lines in the below picture?

A man stands on one side of a river, his dog on the other. The man calls his dog, who immediately crosses the river without getting wet and without using a bridge or a boat. How did the dog do it?

The horse jumps over the king.
Strangely there is absolutely no scratch on him.

Can anyone explain, how is this possible?

I am the fastest animal but cannot climb the tree. What am I?

I have 50 feet long of cloth, I need to create 50 handkerchiefs each size of 1 foot. I take one minute to cut a 1-foot handkerchief. So how long will it take to cut 50 handkerchiefs?