John is the son of Jacob.
So,
Jacob is the_____of John's father?

If your uncle’s sister is not your aunt, what relation is she to you?

Until it is measured, not known. Yet how you miss it when it has gone. What is it?

While going to your grandmother's house, you counted Twenty houses on the right side. While returning back to your home, you counted Twenty houses on the left side.

How many houses are there between your home and your grandmother's home?

10 people came into a hotel with 9 rooms and each guest wanted his own room. The bellboy solved this problem.
He asked the tenth guest to wait for a little with the first guest in room number 1. So in the first room, there were two people. The bellboy took the third guest to room number 2, the fourth to number 3, ..., and the ninth guest to room number 8. Then he returned to room number 1 and took the tenth guest to room number 9, still vacant.
How can everybody have his own room?

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

A patient was diagnosed with some ailment. He was given five different tablets to take at night at an interval of 15 minutes.

How long will it take the patient to consume all the five tablets?

What is red and smells like blue paint?

I have a hole in my back and legs I lack.
I live where I can’t breathe and I eat without teeth.
What am I?

What animal walks on four legs in the morning, two legs during the day, and three legs in the evening?

Oedipus, the king of Thebes, figured out the answer to the riddle: