Marty鈥檚 date
Our niece Ennie, nephew Iggy and their friend Marty were born on different dates in December. Ennie鈥檚 birth date is the 19th and Iggy鈥檚 is the 21st. The trio have tried writing down all numbers that can be expressed as a multiple of 19 plus a multiple of 21 plus a multiple of Marty鈥檚 birth date, where in each case the whole-number multiple can be zero or more.
They have managed to express 189 as a sum of multiples, and indeed any higher number can be similarly expressed. But it is impossible to express 188 in this way.
What is Marty鈥檚 birth date?
WIN 拢15 will be awarded to the sender of the first correct answer opened on Wednesday 6 April. The Editor鈥檚 decision is final. Please send entries to Enigma 1635, New 杏吧原创, Lacon House, 84 Theobald鈥檚 Road, London WC1X 8NS, or to enigma@newscientist.com (please include your postal address).
Advertisement
Answer to 1629 Another new year: 267,841,903
The winner Jackie Willmington, Aberystwyth, Ceredigion, UK