13 decks of cards have been mixed. What is the minimum number of cards that must be taken out from the above-mixed cards to guarantee at least one 'four of a kind?

Move three sticks of the spiral below to form a square.

You need to pick one entry from pot A and one from pot B to have a perfect match. Can you do it?

I live in a bowl. I can swim. I have a tail. I also have fins and big eyes. What am I?

Rearrange the letters in "new door" to make one word.

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?

It's a protector.
It sits on a bridge.
One individual can see directly through it, while others wonder what it hides.

What is 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?

Can you find out the missing number in the grid?

I look at you, you look at me, I raise my right, you raise your left. What am I?