Earlier today I set you the following puzzles, each penned by William Hartston, aka Bill off Gogglebox:
1) What is the next number in the following series?
23, 9, 20, 14, 14, 9, 20, 6, ...
2) Mary I; George III, Henry III, James II, George IV, Charles I, ...
Why might Henry I be an appropriate way to end the series?
3) What comes next in the following series?
2.1, 3.5, 3.3, 2.3, 1.3, 2.4, 2.5, 2.6, 1.8 ...
4) What comes next in this series:
1, 2, 9, 12, 70, 89, 97, 102 ...
Solutions
1) 19 – the numbers are the alphabet positions of the first letters of the words in the question.
2) The code is that Mary I is taken to mean the first letter of Mary, George III is the third letter in George, and so on. The whole series, including a final Henry I, therefre spells out the word “monarch”.
3) 2.7 They are the row and column positions on a QWERTY keyboard of the letters in alphabetical order. (2.1 means second row, first letter; 3.5 is third row, fifth letter, etc.)
4) 182: Subtract 1 from each number and you get the numbers that are the same upside down: 0, 1, 8, 11, 69, 88, 96, 101, 181.
Don’t feel too bad if you did’t get that last one. Says Bill: “I came up with it many years ago when talking to a Cambridge mathematician who was about to compete in a puzzle-solving competition against Oxford. He told me that at the end of the formal part of the contest, they had an informal bit where the teams set each other original puzzles and he asked if I could come up with something. The above question was the result. Nobody solved it, though everyone agrees it is completely fair and logical.”
Thanks again to Bill for letting me use these puzzles. Don’t forget to check out his recent book Even More Things That Nobody Knows: 501 Further Mysteries of Life, the Universe and Everything, which is out in paperback in November.
I post a puzzle here on a Monday every two weeks. If you want to propose a puzzle for this column, please email me I’d love to hear it.
I’m the author of several books on maths, as well as the kids book Football School: Where Football Explains the World which tells you loads of amazing stuff parents don’t tell you such as when exactly footballers poo, why eagles are the most common mascot for football teams and how to play football on Mars
You can check me out on Twitter, Facebook, Google+, my personal website or my Guardian maths blog.
