Puzzle of the day · No. 15 · 27 October
A coffee on the house
Schulz gives away every sixth coffee at his shop: five stamps on the card and the sixth is free. How many coffees does Lucky need to buy in order to drink twenty?
Answer: 17. The sixth, twelfth and eighteenth will be free: three out of twenty. So 17 are paid for. Sixteen is not enough: there would still be three free ones, but only 19 in all.
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