People have been left scratching their heads over a that 'should be easy to solve but isn't'. It prompts players to think outside of the box when coming up with a solution - and consider the 'simple' option as sometimes this can be the correct answer.

The puzzle was posted on the thread, 'What are some of the best brainteasers in the ?', and starts: "A poor man walks into a bar and starts talking with a really rich man. The poor man says, 'You know, I know every song in the world. I bet all your fortune and possessions that I can find a song with any name you want'.

"The rich man, laughing, accepts and says that he bets him to find a song with his daughter's complete name in it. Her name is Julie-Monique-Alexandrina.

"A few minutes later, the poor man exits the bar, with the rich man's wallet, car(s) key(s), clothes, etc. He won his bet. How?"

Trying to figure it out, one user guessed Mambo No. 5 by Lou Bega because it includes the names Angela, Pamela, Sandra, Rita, Monica, Erica, Tina, Sandra, Mary, and Jessica.

In agreement, another user added: "I was thinking Mambo No 5. That song has quite a few lady names." While other users couldn't come up with an answer at all - and begged the quizmaster to share the solution.

Sharing the correct answer, they simply said: "He sang Happy Birthday."

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But this isn't the only to have puzzled people in recent days as a question sparked a discussion on social media.

According to creator Tanya Zakowich, who is known as @pinkpencilmath on social media, Google used to ask its job candidates a brainteaser in their interviews - and didn't hire anyone who failed it.

However, in 2013 Google is believed to have scaled back these questions, with former chief of Google human resources telling the New York Times they couldn't "predict anything" and primarily were there to "make the interviewer feel smart".

In a video, she said: "If you don't know the prisoner hat riddle, you're going to love this one. It's a super classic brainteaser that was commonly asked in job interviews at ." Explaining the riddle, she says: "There were four prisoners on a staircase all facing the same direction. A brick wall separates prisoner 4 from the rest."

She says prisoner 1 can see prisoners 2 and 3, while prisoner 2 can only see prisoner 3 and prisoners 3 and 4 cannot see anyone.

"All four prisoners are wearing hats. They are told there are only two black hats and white white hats. However, they do not know the colour of the hats they are personally wearing.

"The prisoners were told to shout out the colour of the hat they're wearing as soon as they know what colour it is." Knowing this, she says the question is: "Who is the first person to shout out correctly - and why?"

Setting out the rules, the prisoners cannot turn around to look at each other, move in any other formation, or take their own hats off.

Did you manage to figure it out? Check the