The purity of gold is measured in karats, with pure gold being 24 karats. other purities of gold are expressed as proportional parts of pure gold. thus 18-karat gold is startfraction 18 over 24 endfraction 18 24, or 75% pure gold; 12-karat gold is startfraction 12 over 24 endfraction 12 24, or 50% pure gold; and so on. how much 2020-karat gold should be mixed with pure gold to obtain 8080 grams of -karat gold? how much 2020-karat gold should be used?