Musk's viral math puzzle has no single answer

A viral puzzle with four answers and none official

The puzzle allows for at least four different results. An image with three lines of equations — headphones, a figure, and a watch — circulated with an English tweet promising a job to whoever solved it: «Can you solve it? If you can, I'll hire you». The account was a parody of Elon Musk, not Elon Musk himself. This detail arrived late to much of the conversation.

The proposed figures range from 11 to 116, with a 666 tip, and no instance has validated a solution. There is also no job offer behind it. What there is, however, is an arithmetic problem with a trick and a much more interesting discussion than the drawing itself.

What does the tweet attributed to Elon Musk say?

The message is brief: a question and a conditional promise of hiring, accompanied by the image. It is the classic format of the hook of recruitment, that which turns a pastime into a talent filter without anyone having demonstrated that it filters anything.

The account publishing it identifies itself as a parody, something several readers pointed out after they had already been debating for half an hour whether the watch was worth two or three. It is necessary to separate the two planes: there is an arithmetic problem and there is a bait. The second explains the spread; the first, the frustrations.

What is the solution to the puzzle?

The most repeated answer is 39. The standard development starts with three pairs of headphones summing 30, from which each pair is worth 10 and each loose headphone, 5. Then, two figures plus a pair of headphones sum 20, so each figure is worth 5. And two watches plus two watches plus a figure sum 13, so each watch is worth 2.

In the last line, there is a single headphone, a figure wearing two headphones and a watch, and a multiplication sign. The result is 5 + (5+10+2) × 2 = 39. The full breakdown, equation by equation, is what is reproduced most often in the comments, and there lies half the interest of the matter.

Why does it come out 44 for many people

The order of operations is to blame. Those who add before multiplying get (5+17) × 2 = 44. Others group the accessories differently and also land on 44. And there is no shortage of those who extend the multiplication to the whole set and go off to 116.

The minority figures respond to the same thing. The 19 appears among those who ignore that the lower figure wears accessories; the 15 and the 14, among those who treat the headphones as loose summands; the 11 and the 12, among those who accept that only what is seen at first glance counts. The 88, the 79, or the 81 have no known development. Each result has its internal logic and its point of arbitrariness.

The detail only seen at a second glance

In the last line, the figure is no longer the same as in the previous ones: it wears headphones and a watch. And there is a single headphone, not two. There lies the entire trick, and it works more as an attention test than as a math problem.

Someone dubbed it lateral thinking, a term used with sarcasm because it is the one usually wielded by selection departments to justify their tests. The scene is recognizable: the candidate who did not see the watch is left out of the process, and not for not knowing arithmetic.

Four equations and five unknowns

Some argue that the statement does not fix the value of the figure with accessories, so the system remains open: four equations and five unknowns, with no determined solution. The question of whether the watch is a Rolex — and how much it would add — does not help to close it.

On the other side weighs another argument: two people are worth the same regardless of what they wear, and valuing differently someone wearing a watch would be discrimination. Under this rule, everything simplifies and the result sinks to 19 or 15. It is an elegant way out to not admit that the detail was missed.

The trap of personnel selection

The hiring hook is what turns a pastime into something else. A puzzle like this does not measure professional competence; it measures tolerance to being evaluated with a trick and to having someone decide your future based on whether you count cascos or pairs of cascos.

And there is the finale: if who promises the job is a parody account, the joke pays for itself. The promise of hiring was never such, which has not prevented several readers from litigating with it seriously.

It is predictable that the image will return every so often with another figure in the headline and the same discussion in the comments. The official answer will not come, among other things because there is no job, no company, and no Elon Musk behind the tweet.