Pure gold is 24 Karat's so the ratio of purity 18 karat gold is: (Number of Karats of Gold chain)/(Number of Karats of pure Gold) this will give us: 18/24 =3/4 The weight of pure gold in 18 Karat Gold will be: (ratio of purity)×(Total weight of chain) =3/4×18 =13 1/2 ounces =13.5 ounces.
<span>18 karat gold contains 75% gold, and 25% other metals in the alloy. 75% of 2.8 ounces yields a gold content of 2.1 ounces. Multiplying .75 times 2.8 will yield the correct result.</span>
