Place the numbers from 1 to 9 in the circles in a manner that each side of the triangle sums up to 17.

What always comes into a house through the keyhole?

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?

I have cities, but no houses. I have mountains, but no trees. I have water, but no fish. What am I?

You need to arrange three 7 and mathematical symbols to form number 1?

How can one talk without saying a single word?

You need to climb ten stairs. At every stair, you can either take one step up or you can jump two steps up.

In how many different ways you can climb 10 stairs?

I am a word that begins with the letter “i.” If you add the letter “a” to me, I become a new word with a different meaning, but that sounds exactly the same. What word am I?

There are four 3-link chains. All you have to do is join them into a big 12-link chain. For joining two closed links, one of the links must be cut and placed onto the other link for closing.

How many minimum links will you have to cut to make the big chain?

Solve the puzzle by telling what does below picture means.