Tricky riddle sees 90% of people give up before finding the answer

A baffling riddle has gone viral on social media as only 10% of people are able to solve it – and you’ll need sharp wits if you want to work out the answer

If you’re keen to shake off the mental fog that’s settled in since Christmas, this riddle could be just the ticket. Brainteasers are brilliant for firing up your grey matter and getting those mental cogs whirring again, particularly after a spell of festive downtime and mind-numbing telly.

Keeping your brain in shape is every bit as crucial as looking after the rest of your body, as a well-exercised mind is far better equipped to ward off conditions such as dementia. Regular mental workouts through puzzles and the like can also enhance your cognitive abilities, sharpen your problem-solving prowess, and even give your mental well-being a lift.

So, if you’re after a cerebral pick-me-up today, you’ve come to the right place. This riddle won’t be a gentle warm-up, though, as it’s said that a whopping 90% of people find themselves stumped when trying to crack it.

You’ll need a sharp eye for detail, top-notch deduction abilities, and a spot of mathematical know-how to navigate this devilishly tricky puzzle. Reckon you’re up to the challenge? Take a look below.

The clip was posted on Instagram by Thomas Mulligan, who revealed that nine out of 10 people can’t solve the question despite it appearing “pretty easy” at first glance. He explained the question was devised by Singapore’s National Institute of Education, and has since become one of the “most famous logic puzzles” on the planet.

The puzzle begins by introducing two blokes, Albert and Bernard, who’ve recently befriended a woman called Cheryl. They’re attempting to suss out her birthday, and to assist them, Cheryl provides a list of 10 potential dates.

The dates she offers are: May 15th, May 16th, May 19th, June 17th, June 18th, July 14th, July 16th, August 14th, August 15th, August 17th.

But here’s the catch – Cheryl reveals the month to Albert and the day to Bernard, with neither knowing what the other has been told. Your task is to figure out Cheryl’s birthday based on the following exchanges between Albert and Bernard.

Albert states: “I don’t know when Cheryl’s birthday is, but I know that Bernard doesn’t know either.”

Bernard responds: “At first I didn’t know Cheryl’s birthday, but now I know.”

Albert then confirms: “Then I also know.”

Can you crack this using the information given? We’ve got the answer waiting just below, so hold off scrolling and take your time working it through.

Answer

Cheryl’s birthday is July 16th.

The brainteaser is certainly challenging, but it’s solvable. Albert is only privy to the month Cheryl was born, yet he declares in his statement that he knows Bernard can’t work it out either with his information, which means the month can’t be one containing a unique day.

This rules out May, as Bernard would instantly know the answer if it were May 19th, and June, as the 18th doesn’t appear in any other months either.

Once Albert has made that statement, Bernard is able to deduce the answer. With May and June off the table, the answer must be the only unique date left between July and August. As the 14th and 17th appear in both months, and the 15th appears in May, the answer must be July 16th.

Did you manage to crack it? Let us know in the comments!