<PRE><B>Question 1048047</B>
A jeweler has four rings, each weighing 24 g, made of an alloy of 15% silver and 85% gold. She decides to melt down the rings and add enough silver to reduce the gold content to 80%. How much silver should she add? 
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Equation:
silver + silver = silver
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4(0.15*24) + 1*s = 0.20(4*24+s)
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Multiply thru by 100 to get::
15*(4*24) + 100s = 20*(4*24) + 20s
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80s = 5*(4*24)
s = (1/16)(4*24)
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s = 6 grams (amt of pure sulver to add)
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Cheers,
Stan H.
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