This old gag caught my eye recently:
As usual in these cases, it’s a trick question.
Turns out it resolves fairly simply when we just “follow the money”.
Start with the $300 being tendered. The desk clerk later refunds $50 and keeps $250 for the room. Of that $50, each friend gets $10 while the bellhop keeps $20. So the final distribution of funds is:
- Hotel: $250
- Bellhop: $20
- Three Friends: $30 ($10 each)
For a total of $300, just as we’d expect.
The misdirection is pointing to the $90 each friend paid ($270 total) and considering that the same category as the $20 taken by the bellhop. Two different things (and the $250 for the room isn’t even in the equation).
Instead, as in the bullet list above, consider the $250 held by the hotel, the $20 held by the bellhop, and the $30 held by the friends. When we consider things all in the same category, the math works out.
But that’s hardly surprising.
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If this tickled your interest, here’s more Fun with Numbers.
Stay numeric, my friends! Go forth and spread beauty and light.
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October 22nd, 2026 at 2:44 pm
It may be an oldie, but it’s a new thing if you’ve never seen it before.
And hence one of my all-time favorite xkcd cartoons: Ten Thousand.
As the cartoon’s hover gag says: Saying “what kind of an idiot doesn’t know about the Yellowstone supervolcano” is so much more boring than telling someone about the Yellowstone supervolcano for the first time.