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?

Astrology starts with the alphabet A, Biology starts with B, Psychology with P and Limnology with L.

Can you find an "ology" that begins with a P?

What is the four-digit number in which the first digit is one-third the second, the third is the sum of the first two, and the last is three times the second?

A shepherd had 18 sheep, out of which, all but ten died.

Can you tell us how many sheep was he left with?

I’m tall when I’m young, and I’m short when I’m old. What am I?

What does this mathematical rebus means ?

What happened when the wheel was invented?

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

A game is being played where eight players can last for thirty-five minutes. Six substitutes alternate with each player in this game. Thus, all players are on the pitch for the same amount of time including the substitutes.

For how long is each player on the pitch?

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?