The Museum of HP Calculators

HP Forum Archive 17

 OT A simple math puzzleMessage #1 Posted by Ken Ratkevich on 6 May 2007, 12:11 p.m. The solution to this puzzle is probably very simple. I will probably be embarrassed by how simple the solution actually is. Ken

 Re: OT A simple math puzzleMessage #2 Posted by Matt Kernal (US) on 6 May 2007, 12:22 p.m.,in response to message #1 by Ken Ratkevich On first glance, 15 seems about right (i.e. 36 minus 21 = 15 and 28 minus 15 = 13). Edited: 6 May 2007, 12:27 p.m.

 Re: OT A simple math puzzleMessage #3 Posted by Chuck on 6 May 2007, 12:33 p.m.,in response to message #2 by Matt Kernal (US) How does the 21 - 13 give 7, then? Edited: 6 May 2007, 12:34 p.m.

 Re: OT A simple math puzzleMessage #4 Posted by Matt Kernal (US) on 6 May 2007, 1:28 p.m.,in response to message #3 by Chuck Good catch. Obviously, I didn't take the time to finish the sequence :-) Good thing my answer was of the non-committal type, with generous use of "escape" language, such as, "On first glance.." and "seems about right..". Now I'm sounding like a politician :-) Matt

 Re: OT A simple math puzzleMessage #5 Posted by Richard Ottosen on 6 May 2007, 1:03 p.m.,in response to message #1 by Ken Ratkevich One solution is 12. I wonder if there are more solutions. :-) -- Richard

 Re: OT A simple math puzzleMessage #6 Posted by Ken Ratkevich on 6 May 2007, 4:21 p.m.,in response to message #5 by Richard Ottosen Hi, Can you describe how you arrived at your solution? Ken

 A simple math puzzle (SPOILER)Message #7 Posted by Gerson W. Barbosa on 6 May 2007, 6:19 p.m.,in response to message #6 by Ken Ratkevich Ken, Perhaps Richard just didn't want to spoil the fun: ```(9+9) + (7+2) = 27 (2+7) + (4+5) = 18 (1+8) + (3+9) = 21 ``` and so on... Regards, Gerson. Edited: 6 May 2007, 6:34 p.m.

 Re: A simple math puzzle (SPOILER)Message #8 Posted by Richard Ottosen on 6 May 2007, 8:08 p.m.,in response to message #7 by Gerson W. Barbosa Ken: I used the same method to get the solution as Gerson. I summed the individual digits to get the next result. Puzzles like this one always make me wonder if there is more than one way to solve them since the rules are very open-ended. Thanks for the challenge. -- Richard

 Re: A simple math puzzle (SPOILER)Message #9 Posted by Gerson W. Barbosa on 6 May 2007, 10:58 p.m.,in response to message #8 by Richard Ottosen Quote: I used the same method to get the solution as Gerson. As a matter of fact, I didn't find the solution. You did. I just got curious and tried to discover how you had found it. If I didn't know the solution beforehand I would have probably voted for 15 and assumed the 21 at right was a typo :-) The following might be easy and has only one solution, to my knowledge: ``` ____ ___ |\/| \ / \ / |\/| ? | | _\/_ /_\ |ŻŻ| ``` Gerson.

 Re: A simple math puzzle (SPOILER)Message #10 Posted by Valentin Albillo on 7 May 2007, 2:33 a.m.,in response to message #9 by Gerson W. Barbosa Yes, this one is very, very old: ``` ----- _|_ | | ----- ``` Best regards from V.

 Re: A simple math puzzle (SPOILER)Message #11 Posted by Antonio Maschio (Italy) on 7 May 2007, 5:39 a.m.,in response to message #10 by Valentin Albillo Please, explain... -- Antonio

 Re: A simple math puzzle (SPOILER)Message #12 Posted by Valentin Albillo on 7 May 2007, 6:17 a.m.,in response to message #11 by Antonio Maschio (Italy) Hi, Antonio: Antonio posted: "Please, explain..." It's actually extremely simple: the first four forms are just the ASCII representation of the shape of the digits 1,2,3, and 4 with their mirror images prepended. The next element thus is to be an ASCII representation of the shape of a 5, with its mirror image prepended. Best regards from V.

 Re: A simple math puzzle (SPOILER)Message #13 Posted by Antonio Maschio (Italy) on 7 May 2007, 11:01 a.m.,in response to message #12 by Valentin Albillo Off! I'm so dumb... -- Antonio

 Re: A simple math puzzle (SPOILER)Message #14 Posted by Gerson W. Barbosa on 7 May 2007, 12:01 p.m.,in response to message #13 by Antonio Maschio (Italy) Actually this is not so easy, as we tend to see the symbols as letters: ```MVXM ``` Roman numerals? :-) Gerson.

 [OT & NT] - To Valentin: You've got mail :-)Message #15 Posted by PeterP on 7 May 2007, 12:50 p.m.,in response to message #10 by Valentin Albillo Thanks!! Cheers Peter

 Re: [OT & NT] - To Valentin: You've got mail :-)Message #16 Posted by Valentin Albillo on 7 May 2007, 7:14 p.m.,in response to message #15 by PeterP Hi, PeterP: Actually, I've got nothing (yet). I've checked the usual accounts but nothing there from you, unless you were telling me that a recently deceased relative has left me 6 million sterling pounds in his will and that I should send my bank account details for the transfer of the funds to be made. If that was the case, sorry but I decline the kind offer, I'm far too modest a person, as everyone knows, and wouldn't know what to do with that much money, it would spoil my healthy habits for sure. Now seriously, did you remember to include the string "HP CALCS" in the subject line, as instructed in my web page ? Else, *anything* sent to my usual account (via this MoHP form, for example) without including such a text string in the subject is automatically and invisibly redirected to the trash bin, sight unseen. Thanks for whatever it was and Best regards from V.

 Re: [OT & NT] - To Valentin: You've got mail :-)Message #17 Posted by PeterP on 7 May 2007, 9:27 p.m.,in response to message #16 by Valentin Albillo my mistake, really sorry. Forgot about the subject line. Mistake corrected. Thanks for the reminder! Cheers Peter

 Re: A simple math puzzle (SPOILER)Message #18 Posted by Ken Ratkevich on 7 May 2007, 4:08 a.m.,in response to message #7 by Gerson W. Barbosa Oh, I see now! I got off on the wrong foot since 99/72 = remainder of 27 and 54/27 = remainder of 18. I lost it after that. At least the solution was a little bit tricky. I don't need to be that embarrassed. Ken

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