What always comes into a house through the keyhole?

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?

There’s a girl who has a large family. She has an equal amount of brothers and sisters, but each brother only has half as many brothers and sisters. What’s the correct amount of brothers and sisters?

I have teeth but i don't bite. Who Am I ?

John was a very careless driver, so his owner Jacob gave him an offer that he will get an incentive of Rs.30 for every bottle box he delivered without breaking it and he will be charged Rs.90 for every bottle box he broke. Jacob gave John 100 bottles-box to deliver. After delivery, Jacob paid John Rs.2400. How many bottles-box did John break?

In the four images below, can you find the odd one out?

You board a train. The train will have to enter a tunnel soon. You are claustrophobic. Which place is the best for you to sit?

How many triangles are there in the picture below?

What number should come in place of the question mark below?

Two friends Smith and Andrew were talking about the bravery of their families. Smith told great stories about his courageous grandfather who fought for Britain in "World War I". Andrew told that his grandfather was so brave that in 1919 just after the war he was honoured with a bravery medal with the words "For our Courageous Soldiers In World War I" embedded into it. Smith knows that his friend is lying. How?