## College Algebra (10th Edition)

$40$ grams.
Let $y$ be the amount of $12$ karat gold, then $60-y$ is the amount of pure gold. Then our equation is: $y\cdot\frac{12}{24}+(60-y)\frac{24}{24}=60\cdot\frac{16}{24}\\0.5y+60-y=40\\20=0.5y\\40=y$