🔢 Numbers ★★★☆☆ +16 points #13

The Missing Thousand

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Open — answers are being collected The solution goes up on 31 August. Send in your answer before then and it counts for full points — you will not be told whether it is right until the reveal.

Three friends take a room. The receptionist asks for 30 000 som, so each of them puts in 10 000.

Later the manager notices the room is only 25 000 that night, and sends a porter up with 5 000 som.

On the stairs the porter thinks: five thousand does not divide evenly by three. So he gives each friend 1 000 som back and quietly keeps 2 000 for himself.

🧮Now the trap. Each friend paid 10 000 and got 1 000 back, so each paid 9 000. Three times 9 000 is 27 000. The porter has 2 000. And 27 000 + 2 000 = 29 000 — but they started with 30 000. Where is the missing 1 000 som?

There is no missing money, of course. The sum above adds two numbers that must never be added together. Find the false step — and then prove you have found it by following the money properly.

Answer to type: of the 27 000 som the friends actually paid, how many som ended up in the hotel's till?

💡 I want a nudge

Ask what the 27 000 is made of. Does the porter's 2 000 sit inside it, or outside it?

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