I’m tall when I’m young, and I’m short when I’m old. What am I?

Considering the below equation:

V + II - VI = 10
IV - X + VIII = 20
IV - VII + VI = 30

Then, I + II + III = ?

You see a boat filled with people, yet there isn’t a single person on board. How is that possible?

You bought me for dinner but never eat me. What am I?

Two old friends, Jack and Bill, meet after a long time.

Three kids
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?

John was visiting his friend Jacob. He found out that his friend's wife had just killed a burglar in self-defense.
John asks Jacob about what happened and he told that "His wife was watching television when suddenly the bell rang. She thought that it is her husband Jacob but she found the burglar who attacked her instantly and she got so frightened that she killed the burglar immediately with the knife.
John asked the police to arrest his friend's wife. Why?

What is the coolest letter in the alphabet?

You knock a Table over in the library, and suddenly 20 eyes are looking at you.

How is a fly different from a mosquito?

What can run but never walks, has a mouth but never talks, has a head but never weeps, has a bed but never sleeps?