A seemingly simple puzzle has the users of Mumsnet completely stumped.
The user known as PeerieBreeks uploaded the puzzle with the caption "can't understand how so many people on Facebook have it so completely wrong."
Hundreds of people responded, but few managed to get it right. Give it a crack below...
A man buys a horse for $60.
He sells the horse for $70.
He then buys the horse back for $80.
And sells the horse again for $90
In the end, how much money did he make or lose?
Or did he break even?
The answer is $20. He makes $10 on each transaction, so makes $20 in total, despite buying the horse back for $10 more than he sold it for.
How long did it take you to solve?