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?

What is the fewest number of coins that would be required in order to make sure each and every coin touches exactly three other coins?

As you can see that fifteen matches have been used to form an arrangement. What you have to do is remove any six of them to make them ten.

Christina has four daughters, and each of her daughters has a brother. How many children does Christina have?

Analyze and find the missing item in the sequence:
16, 06, 68, 88, __, 98

Three people enter a room and have a green or blue hat placed on their heads. They cannot see their own hat but can see the other hats.
The colour of each hat is purely random. They could all be green, blue, or any combination of green and blue.
They need to guess their own hat colour by writing it on a piece of paper, or they can write 'pass'.
They cannot communicate with each other in any way once the game starts. But they can have a strategy meeting before the game.
If at least one of them guesses correctly they win $10,000 each, but if anyone guesses incorrectly they all get nothing.
What is the best strategy?

Two guards were guarding the camp.Guard-1 was looking towards the south to make sure no threat is coming from the road.Guard-2 was looking at the north to make sure no threat is coming from the top. Suddenly Guard-1 ask the Guard-2 why he is smiling?How Guard-1 knows that Guard-2 is smiling?

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

Why do we preferably have round manhole covers and not square ones?

Count the number of triangles in the picture below: