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

A guard is positioned at the one side of the bridge saying ‘A’. His task is to shoot all those who try to leave from ‘A’ to the other side and say ‘B’. He also need to welcome the person who comes from another side ‘B’ to his side ‘A’. The guard comes out of his post every 1 hour and looks down the bridge for any people trying to leave. You are at side ‘A’ and wish to go to another side ‘B’. you also know that it would take 1:45 hr to cross the bridge. How will you cross the bridge?

Find the next number in the series.
1 10 24 43 67 ?

A seven-year-old kid challenged his classmates that he can make the number one disappear by adding something to it.

How can he do that?

If I remove one from eleven it becomes Ten and if I remove one from nine also becomes Ten. How?

Can you spot the man between the coffee bean in the picture below ?

Three people enter a room and have a green or blue hat placed on their heads. They cannot see their own hat but can see the other hats.
The colour of each hat is purely random. They could all be green, blue, or any combination of green and blue.
They need to guess their own hat colour by writing it on a piece of paper, or they can write 'pass'.
They cannot communicate with each other in any way once the game starts. But they can have a strategy meeting before the game.
If at least one of them guesses correctly they win $10,000 each, but if anyone guesses incorrectly they all get nothing.
What is the best strategy?

Place a mathematical symbol between the numerals 5 and 9 in such a way that the resulting number is greater than 5 but smaller than 9.

Remove two matchsticks to make the below equation correct.

Yesterday I fell from 30 feet high ladder but I don't get hurt. Why?