Chris Angelico <ros...@gmail.com> writes: > On Thu, Sep 7, 2017 at 5:59 PM, Marko Rauhamaa <ma...@pacujo.net> wrote: >> Dennis Lee Bieber <wlfr...@ix.netcom.com>: >> >>> On Wed, 06 Sep 2017 10:37:42 +0300, Marko Rauhamaa <ma...@pacujo.net> >>> declaimed the following: >>> >>>> >>>>Which reminds me of this puzzle I saw a couple of days ago: >>>> >>>> 1 + 4 = 5 >>>> 2 + 5 = 12 >>>> 3 + 6 = 21 >>>> 8 + 11 = ? >>>> >>>>A mathematician immediately comes up with a "wrong" answer. >>> >>> I'm coming up with "96", on the basis that the "+" is a >>> placeholder for a non-standard operation >> >> That's a mathematician's "wrong" answer. Stefan Ram's answer is the >> intended one. > > Ian's answer has better justification. I'm going to support "banana".
Solving puzzles like this should come with a pleasing "ah!" moment which usually comes from finding a simple rule or explanation. An arbitrary answer is always possible, but it is rarely a rule, and although arbitrary rules are also possible, they will rarely be simple. (On average a rule will need at least as many symbols to be described as the puzzle itself[1].) The trouble with this puzzle is that has at least two answers that are simple rules and, to my mind, neither has a pleasing "ah!" associated with it. [1] Obviously this is not formal but it could be made so by reference to algorithmic complexity. -- Ben. -- https://mail.python.org/mailman/listinfo/python-list
