The number of bottles in a full box is 12.
Explanation
Suppose, the number of bottles in a full box is [tex]x[/tex]
So, the number of bottles in three full boxes [tex]=3x[/tex]
Now, two more boxes are added, both of which have one fewer bottle than the other three. So, the number of bottles in these two boxes [tex]= 2(x-1)[/tex]
As there were 9 bottles initially and now there are 67 bottles in the fridge, so the equation will be....
[tex]9+3x+2(x-1)=67\\ \\ 9+3x+2x-2=67\\ \\ 5x+7=67\\ \\ 5x=67-7\\ \\ 5x=60\\ \\ x=\frac{60}{5}=12[/tex]
Thus, the number of bottles in a full box is 12.
