Question 323122
Let x=amount of alloy Brianna is using.

The amount of gold is then

.10x+.71(.5)=.466(.5+x)

Solve for x to find how much alloy Brianna used.

Since .10x+.71(.5) is the amount of gold in the alloys, plugging this value into .10x+.71(.5) and multiplying by 209.31 should give 81.28.