Replace the question mark with the correct number.

2 + 2= 4
3 + 3= 18
4 + 4= 48
5 + 5= ?

What kind of tree can you carry in your hand?

How will you measure 15 minutes using two hourglasses of 7 minutes and 11 minutes respectively?

John named his first son Alpha, second Beta, third Charlie and fourth Delta. What is the fifth son's name?

What jumps when it walks and sits when it stands?

If we add four times the age of John four years from now to five times his age five years from now we get ten times his current age.

How old will John be two years from now?

What occurs twice in a week, once in a year but never in a day?

What is both possible and impossible at the same time?

Two fathers and two sons went fishing one day. They were there the whole day and only caught 3 fish. One father said, that is enough for all of us, we will have one each. How can this be possible?

Once upon a time, there was a castle on a square island. The entire island was surrounded by a 14m wide trench. The Romans had wanted to invade the castle and had brought a few wooden planks along with them to facilitate themselves in crossing the moat. The planks were however found to be only 13m long.

The Romans still managed to cross the trench. How did they do it?