Finding a NumberDate: 4/13/96 at 16:47:51 From: Anonymous Subject: Number Riddles My ones digit is twice my tens digit. One of my factors is 3. What am I? Date: 4/17/96 at 13:0:32 From: Doctor Joshua Subject: Re: Number Riddles Hi! I was just staring at this problem when I realized 12 works. And then it occurred to me that 24 works, and 36, and even 48. But that's all the tens that work (and it has to be because if one existed that was in the sixties, its unit digit would have to be 12!). Then there are hundreds, and by process of elimination, 312 works, then so do 324, 336, etc. By analogy 612 etc. works, and so does 912 etc., and on, and on. I hope this is what you were asking. -Doctor Joshua, The Math Forum |
Search the Dr. Math Library: |
[Privacy Policy] [Terms of Use]
Ask Dr. Math^{TM}
© 1994-2015 The Math Forum
http://mathforum.org/dr.math/