You can put this solution on YOUR website! Let x=the tens digit
Then 2x=the units digit
Now we are told that:
x+2x=12 collect like terms
3x=12 divide each side by 3
x=4----tens digit
2x=2*4=8 units digit
CK
the number is 40+8 or 48
4+8=12
12=12
Hope this helps---ptaylor