12% of the resulting alloy is gold
Here, we want to calculate the percentage of the resulting alloy that is gold
We proceed as follows;
(32% of 6mg) + (2% of 12mg)
That would be;
1.92 + 0.24 = 2.16
What means that of the total (6mg + 12mg) , 2.16 mg is gold
Thus the gold percentage will be;
[tex]\frac{2.16}{18}\text{ }\times\text{ 100 = 12 percent}[/tex]