Question 943103
Gold is alloyed with different metals to make it hard enough to be used in jewelry. The amount of gold present in a gold alloy is measured in 24ths called karats. 24-karat gold is 2424 or 100% gold. Similarly, 18-karat gold is 1824 or 75% gold. How many ounces of 18-karat gold should be added to an amount of 12-karat gold to make 4 ounces of 14-karat gold? 
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let x=amt of 18 karat gold should be added
4-x=amt of 12 karat gold should be added
.75x+.50(4-x)=4*7/12
.75x+2-.50x=7/3
.25x=7/3-6/3=1/3
x=1/(3*.25)=1/.75=4/3
How many ounces of 18-karat gold should be added? 4/3