It walks on 4 when its young, walks on 2 when it's older, and walks on 3 when its very old?

Can you place six X (crosses) in below board without making three in a row in any way ?

In one of the popular batman series movie "Batman Forever", there was a riddle that goes like "Tear me off and then scratch my head and I was red then and now I am back. Who am I?

what does this below rebus represent identXQQQQQME

If it took eight men ten hours to build a wall, how long would it take four men to build it?

Can you convert the number zero(0) into a positive number using just one mathematical operator ?

In a stable, there are men and horses. In all, there are 22 heads and 72 feet. How many men and how many horses are in the stable

A few friends are enjoying their sea voyage in a boat full of apples. On the way, they felt hungry and thus decided to eat the apples. Together, they ate two dozen of apples. When they have eaten the apples, will there be any change in the water level?

I cannot talk, but I always reply when spoken to. What am I?

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