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?

A certain street contains 100 buildings. They are numbered from 1 to 100. How many 9's are used in these numbers?

Solve the mathematical equation in the picture below.

Below is the sum of symbols in each row and column in the figure. Analyzing the figure, can you find out the value of the symbols?

I get hot but I never sweat,
I cook food but I am not a chef,
I have a door but you can't enter me,
I have a light but I am not a lamp.
Who am I?

A seven-year-old kid challenged his classmates that he can make the number one disappear by adding something to it.

How can he do that?

Use only one mathematical symbol and all numbers (0-9) to get a sum of 99

Can you replace the question mark with the correct letter?

6 + 6 + 6 = N
7 + 7 + 7 = E
8 + 8 + 8 = R
0 + 0 + 0 = ?

What does this mathematical rebus means ?

How many points are there on the globe where, by walking one mile south, then one mile east and then one mile north, you would reach the place where you started?