Square clocks
In, say, 5-clock arithmetic, counting runs from 1 to 5, but starts again at 1 when 6 is reached. So, in 5-clock arithmetic, 3 + 4 = 2 and so on. Anne, Brian and Cate have been investigating x-clock arithmetic, where x is 2 to 15 inclusive. They have each discovered a two-digit square which, expressed in their three different clocks, gives the same number y.
If I told you the value of y, you could tell me the value of the square and the three values of x they were considering.
WIN £15 will be awarded to the sender of the first correct answer opened on Thursday 21 April. The Editor’s decision is final. Please send entries to Enigma 1639, Â鶹´«Ã½, Lacon House, 84 Theobald’s Road, London WC1X 8NS, or to enigma@newscientist.com (please include your postal address).
The answer to Enigma 1633, and the winner, will appear next week.
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