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HP Forum Archive 16

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OT - date digit challenge
Message #1 Posted by Don Shepherd on 6 Apr 2006, 10:56 a.m.

OK guys, something light.

Yesterday it was 01:23:45 6/7/89. Big deal. I liked 01:23:45 6/7/89 better anyhow.

Now, for the challenge. What was the last date that had all odd number digits? When will the next date be with all odd digits?

      
Re: OT - date digit challenge
Message #2 Posted by bill platt on 6 Apr 2006, 11:12 a.m.,
in response to message #1 by Don Shepherd

November 29, 2005 January 1, 2007

            
Re: OT - date digit challenge
Message #3 Posted by Don Shepherd on 6 Apr 2006, 11:44 a.m.,
in response to message #2 by bill platt

Hey Bill, that's right if you only consider the 2 digit year. What if you consider the 4 digit year?

                  
Re: OT - date digit challenge
Message #4 Posted by bill platt on 6 Apr 2006, 11:54 a.m.,
in response to message #3 by Don Shepherd

There's no difference. Odd numbers are a function of the last digit.

Or do you want all *digits* to be odd?

In that case, you hav to go back to Nov 29, 1999 and forward to Jan 1, 3111!

                        
Re: OT - date digit challenge
Message #5 Posted by Don Shepherd on 6 Apr 2006, 12:03 p.m.,
in response to message #4 by bill platt

Yes, you are right, I didn't explain it well enough. I wanted all digits to be odd.

Nov 19, 1999

                              
Re: OT - date digit challenge
Message #6 Posted by bill platt on 6 Apr 2006, 12:11 p.m.,
in response to message #5 by Don Shepherd

oh, roight. sorry.

Now, same problem as before, except that if you add up all the digits, the sum must also be odd. (both of these answers are even).

Edited: 6 Apr 2006, 12:13 p.m.

                                    
Re: OT - date digit challenge
Message #7 Posted by Don Shepherd on 6 Apr 2006, 2:22 p.m.,
in response to message #6 by bill platt

Bill, you're a crafty guy!

11/9/1999

1/11/3111

Neither of which has ANYTHING to do with my teaching portfolio, which I'm supposed to be working on today.


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