Count the number of triangles in the below picture?

I make two people out of one. What am I?

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

If there are fifteen crows on a fence and the farmer shoots a third of them, how many crows are left?

In a science lab, a petri dish hosts a healthy colony of yeast for an experiment. Now every minute, all the yeast cells divide into two. At noon, there was just a single cell of yeast and at 1:22, the Petri dish was half full. Can you calculate when the dish will be full of yeast?

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?

There are two candles. Both will only burn exactly for an hour. How will you use these two candles to measure forty-five minutes?

A prisoner is told: "If you tell a lie, we will hang you and if you tell the truth, we will shoot you." What did the prisoner say to save himself?

He does not have any heart but still, He manages to live.
If you kill him, you will eventually die but yet you kill him.
He cannot run, who is He?

I make a loud sound when I’m changing. When I do change, I get bigger but weigh less. What am I?