Question 547683
So I will let a represent the tens digit of the number I am looking for and b represent the ones digit.  (so my number will end up in the form ab).

Since the sum of the two digits is 9 this means:
{{{a+b=9}}}    (1) 

Also, since the number is 12 times the tens digit, this means:
{{{a*12=ab}}} ((note: ab is the whole number NOT a*b))
This can be rewritten as 
{{{10*a+2*a=10*a+b}}}
so 
{{{2*a=b}}}    (2)
Substituting (2) into (1) we get:
{{{a+2*a=9}}}
{{{3a=9}}}
{{{a=3}}}

And so {{{b=2*3=6}}}


So our number is 36.  

HOpefully this helps, let me know if you are still unsure:)