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### Finding a Number

```
Date: 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

-Doctor Joshua,  The Math Forum

```
Associated Topics:
Middle School Word Problems

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