<PRE><B>Question 137341</B>
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 18/24, or 75% pure gold; 
12 karat gold is 12/24, or 50% pure gold, and so on. 
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How much 12 karat gold should be mixed with pure gold to obtain 60 grams of 16 karat gold? 
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Pure gold DATA:
Amt. = x oz ; Amt of gold = x oz
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12 karat gold DATA:
Amt = 60-x oz; Amt of gold = 0.50(60-x) = 30 -0.5x oz
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16 karat Mixture DATA:
Amt = 60 oz; Amt. of gold = 16/24(60) = (2/3)(60) = 40 oz 
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EQUATION:
gold + gold = gold
x + 30-0.5x = 40
0.5x = 10
x = 20 oz (Amount of pure gold in the  mixture)
60-x = 40 oz (Amount of 12 karat gold needed for the mixture)
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Cheers,
Stan H.</PRE>