Question 528257
I am a 2-digit number.
<pre>
Let t = your tens digit
Let u = your units digit
</pre>
The sum of my digits is 6. 
<pre>
    t + u = 6
</pre>
My units digit is 2 times my tens digit.
<pre>
        u = 2t

So you have this system of equations:

    t + u = 6
        u = 2t

Substitute 2t for u in t + u = 6

   t + 2t = 6

       3t = 6
     
        t = 2

u = 2t = 2(2) = 4
</pre>
Who am I?
<pre>
You are the number 24. 

Edwin</pre>