Sunday Times Teaser 3120 – Bus Stop Blues
by Susan Bricket
Published Sunday July 17 2022 {link)
While waiting for buses, I often look out for interesting number plates on passing cars. From 2001 the UK registration plate format has been 2 letters + a 2-digit number + 3 more letters, the digits being last two of the year of registration with 50 added after six months (for example in 2011, the possible numbers were 11 and 61). I spotted one recently with its five letters in alphabetical order, all different and with no vowels. Looking more closely, I saw that if their numerical positions in the alphabet (A = 1, B = 2 etc.) were substituted for the 5 letters, their sum plus 1 was the 2-digit number and the sum of their reciprocals was equal to 1.
Send the 7-character registration.
Very straightforward this week.
Using Brian’s decompose() function of enigma 501.
Too cheap? Too dirty?
Variation on theme avoiding floating point operations