It seems like quite an easy equation, so why does no-one know the answer?
The infuriating riddle has been shared over 1,300 times since it was posted
online four days ago.
It has also received hundreds of comments from confused users, one wrote: “The
question is too ambiguous and needs refining, that is the answer.”
While many more gave what they thought was the correct answer, some said two,
four and seven.