What is the fewest number of coins that would be required in order to make sure each and every coin touches exactly three other coins?

I am lying and I always lie. Tell me whether I am lying or telling the truth.

A couple went on a climbing trip. But only the husband returned from the vacation and said that his wife slipped off while climbing and died. On investigating, the local sheriff arrested him saying, 'Your travel agent called. You murdered your wife.'

The man did not inform anyone about the trip. Then how was the agent so sure that it was a murder?

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

An artist while painting a scenic beauty, decides to paint three layers of blue colour on the sky.

Which layer will go on the first?

John said, "If yesterday was tomorrow, today would be Friday."

When did John make this statement?

The centre of the third figure is empty. What digit should fit inside?

You have two buckets of 11 liters and 6 litres.
How can you measure exactly 8 litres?

Consider this about a word: The first two letters signify a male, the first three letters signify a female, the first four letters signify a great, while the entire world signifies a great woman. What is the word?

John can place six large boxes or nine small boxes into a carton.

Can you find out in how many cartons can he place sixty-six boxes in total?