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Puzzle #243: Help end the number-related chaos at my local shop

Can you solve this week’s arithmetical puzzle, Emmental arithmetic? Plus the answer to puzzle #242

11 October 2023

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#243 Emmental arithmetic

Set by Alison Kiddle

Chaos reigned during my last visit to Cheese Louise, the local delicatessen. Two customers both claimed to have picked ticket number 6 from the machine that dispenses these to show who is next to be served. For such machines, the numbers appear like those on a calculator.

“You can’t both be number 6,” said Louise, the owner. “One of you must be number 9. I think the only fair thing to do is serve you both after numbers 7 and 8.”

“This system is terrible,” she told me later. “If there are four customers in the shop, there can…

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