A baffling brainteaser challenge to find the ‘missing pound’ has appeared on social media – and it has certainly got people guessing.
Everyone has at one time or other been sat at a restaurant table trying to figure out how to split a complicated bill.
However, a riddle of three pals, each throwing in an equal amount to settle a bill should be pretty simple, reports MirrorOnline.
But a video shared on TikTok has gone viral after users were left confused by the conundrum.
The video begins with a segment featuring the voiceover saying: “Okay someone explain this to me, because I just don’t get it.”
Three friends go out for dinner at a restaurant and split the bill, each throwing in £10, making a total of £30.
The meal only came to £25 so the waiter has to give them £5 in change.
Unsure of how to split it equally between the three customers, he returns £1 each, and keeps £2 for himself.
After the friends are given £1 back, so they have now only paid £9 each instead. That makes £27, plus the £2 the waiter kept, making £29.
So where has the extra pound gone?
Solving the puzzle relies on looking at it a different way – and it’s incredibly simple.
The pound is not missing at all, and the riddle is an example of informal fallacy, meaning the error lies in the reasoning.
It becomes clear when you set out the sums in a different format. If you add up the £25 cost of the meal, the £1 given to each of the friends, and the £2 the waiter keeps, the total is £30.
The trick comes in the wording of the riddle, where it suggests adding the £2 the waiter kept to the £27 the friends have paid.
The £2 for the waiter has already been included in the £27 total, as the bill was originally only £25. Then add on the £3 given to each of the friends to the total of £27 and it all starts to make a lot more sense.
£25 + £1 + £1 + £1 + £2 = £30.