Question 133606
Let x = 10's digit
Let y = unit's digit
:
The sum of the digits of a two digit counting number is 12
x + y = 12
:
the ratio of the units' digit to the tens digit is 1 to 2.  
{{{y/x = 1/2}}}
Cross multiply
1x = 2y
:
Substitute 2y for x in the 1st equation
2y + y = 12
3y = 12
y = 12/3
y = 4 is the units digit
Then
8 = 10's digit
:
What is the number? It's 84