Only 5 per cent of people can solve 'impossible' farm animal puzzle

One particularlybaffling riddle about farmyard animalshas a straightforward answer, but many people find themselves completely stumped by it.

Some creative thinking, patience and confidence in your own mental abilities should help you crack this riddle, which poses: "A farmer has 10 rabbits, 20 horses and 40 pigs. If we assume all of his horses are pigs, how many horses does the farmer have?"

If you can't manage it, don't fret. We have a hint beneath the picture below. According to the brainteaser featured on Baba Mail,only five per cent of people can solve it. Clue: just trust your gut on this one.

The wording in the riddle is designed to confuse you, but you simply need to use some common sense. If you remain baffled, see the solution below.

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Answer: the answer is naturally 20 horses. Baba Mail explained: "20 of course. Assumptions can't change the fact that horses are horses."

If you found the solution rather irritating, that's perfectly understandable too. Many people think and behave very differently to others and some answers that seem obvious to you might not be apparent to others. Brainteasers are an excellent way of keeping your mind sharp, but they can frequently deceive us.

Certain optical illusions can leave us feeling thoroughly bewildered, for example. The Dean McGee Eye Institute explained: "There are occasions when the brain is unsure of what it sees. Optical illusions occur when your eyes are presented with colours, lights, patterns, borders or areas of contrast that mislead the brain.

"It tries to piece together images using optical clues, learned assumptions and past visual experiences. In these cases, there is a difference between the reality of what you see and what your brain thinks you see. As a result, your brain makes a guess and is tricked into seeing something that does not exist, or it struggles to decide between alternating versions of an image."

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Tackling tricky puzzles, brainteasers and optical illusions could boost your mental abilities, enhance productivity and sharpen memory, though. It's unlikely to cause any damage whatsoever if you regularly tackle such challenges.

Nicole M Avena, PhD, assistant professor of neuroscience at the Mount Sinai School of Medicine in New York City and visiting professor of health psychology at Princeton University explained: "While some studies show that brain training games are not effective, the recollection and work that the brain does during these games keeps your mind fresh and alert... Brain functions that you practise during these games-and the repetition of them-can help improve response time and sharpness."