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The Actuary The magazine of the Institute & Faculty of Actuaries


In your (very interesting) February editorial you informed us that Nikola Tesla, the father of many of our electrical developments, presents an interesting case of extreme ‘triphilia’: … at meals, he would insist on (3+3)x3 = 18 pieces of cutlery, and 18 napkins…

I am sure most readers wondered, as I did, why the given relationship between 3 and 18 was so special. I emailed a segment of your editorial to a friend of mine (I thought he would be interested in the discussion of ‘abduction’) and in his reply he supplied the following rigorous demonstration of how absurd the ‘(3+3)x3 = 18’ thing really is. Here is what my friend wrote:

’Thanks for the abduction article; very interesting… except… that (3+3)x3 = 18 business is a bit ridiculous: 0 = 3-3; 1 = 3/3; 2 = (3+3)/3; 3 = 3; 4 = 3+3-(3+3)/3; 5 = 3+3-3/3; 6 = 3!; I could go on…’

Pretty amusing, I thought it was. Can you enlighten us?