Just 10 percent of people can solve this 'impossible' problem - qht it means if you can

The Wason Test aimed to test people's logic, butit is still as taxing as it ever was and nine out of 10 people get the answer it wrong

A head-scratching brainteaser has emerged and just 10 percent of people can solve this 'impossible' problem.

Only those who are a genius can work out the answer to the puzzle and if you are one if you solve it. Created in the 1960's, the Wason Test aimed to test people's logic. But the brainteaser is still as taxing as it ever was and nine out of 10 people get the answer it wrong. Each person is shown four cards and each contains an odd and even number, plus a blue or green colour.

The instructions say: "If a card shows an even number on one face, then its opposite face is blue. Which cards must you turn over in order to test this idea, without turning over any unnecessary cards?" Those who are a genius will know the answer: "You're only supposed to lift two cards, the even number and the green colour". It is confusing, psychologists believe, because it uses numbers and colours but is far easier with a topic which is socially relevant.

The relevancy of the subject makes the teaser more interesting for those involved and they are more likely to find a solution. Those who solve the brainteaser correctly improves when the riddle is has a certain context. A similar test involving ages and drinks which are featured on the cards in an attempt to find underage drinkers had a far higher success rate.

There was a follow-up theory younger people were more likely to solve an 'if-then' puzzle when it has practical benefit. Other analysis of the test says people usually fail because the word "if" is misinterpreted. Peter Wason, was the creator of the brainteaser, and was an English psychologist who died in 2003.

In another brainteaser posted by The Mirror 99% of people cannot spot a hidden thief in an image. Some brainteasers mean you have to focus and analyse images with those able to do it fastest in the top percent of viewers. This puzzle shows a Halloween costume party with everyone dressed up in fantastic costumes.

Your job is to spot the thief in the party, and if you can do it in under 11 seconds you are among the sharpest in the country. If you were able see the crafty thief hiding amongst the crowd at the party in this time then you are certainly a sharp customer. Here is a hint, the image is full of bright colours and detail to distract the eye - you have to try and look past this at what people at the party are doing, rather than what they are wearing.