When Jack was six years old he hammered a nail into his favourite tree to mark his height. Ten years later at age sixteen, Jack returned to see how much higher the nail was. If the tree grew by five centimetres each year, how much higher would the nail be?

John was running from 40 thieves. John has got 3 gold boxes which weigh as 4kg, 2kg, and 1kg respectively. A witty man asked John to stay with him for seven days in exchange for 1kg gold per day. John needs to stay there for seven days and also do not want to give the witty man any advance. How can John pay for his seven days stay?

Why is the Hole below a Lock?

By removing one matchstick and adding one matchstick, can you convert the word "ZOO" to an animal name?

Can you name an animal whose killing cannot be performed without spilling your own blood?

What has no start, end, or centre?

The day after tomorrow will be three days before Tuesday. Can you find out what is today?

The cream is heavier than Milk. True or False?

Prove that the below maths equation is true.

8 + 8 = 91

What is the next number in this series?

4,12,84,3612....