Our product and our sum always give the same answer. Who are we?

Solve the following series:
AZ, GT, MN, __, YB

There is one thing that goes round the house and also inside the house but never even share a brief touch. What is it?

Why 1729 is a magic number? Answer Logically.

Rahul decided to meet Simran so he boards a local train from Bombay station. Just after the station, there is a 1km long tunnel. The train starts and is now accelerating. Rahul is a claustrophobic guy, so what is the best position for him to sit?

If a zookeeper had 100 pairs of animals in her zoo, and two pairs of babies are born for each one of the original animals, then (sadly) 23 animals don’t survive, how many animals do you have left in total?

Two old friends, Jack and Jill, meet after a long time, and discussing as:

Jack: Hey, how are you, man?

Bill: Not bad, got married and I have three kids now.

Jack: That's awesome. How old are they?

Bill: The product of their ages is 72 and the sum of their ages is the same as your birth date.

Jack: Cool..But I still don't know.

Bill: My eldest kid just started taking piano lessons.

Jack: Oh, now I get it.

How old are Bill's kids?

There was a greenhouse.
Inside the greenhouse, there is a white house.
Inside the white house, there is a red house.
Inside the red house, there are lots of babies.

What is It?

What can run but never walk, have a mouth that never speaks, have a head that never weeps, and have a bed but never sleeps?

I was speeding and ran through a stop sign, yet two traffic officers who were there do nothing about it.

why?