A jeweler has a 20 gram ring that is 60% gold and 40% silver. He wants to melt it down and
add enough gold to make it 80% gold. How many grams of gold should be added?	Choices.
A) 4 grams  B) 8 grams  C) 12 grams  D) 16 grams  E) 20 grams
Gold concentration = weight of gold/total weight   0.80 =20*0.60+x/20+x   12 + x = 16 + 0.8x   0.2x = 4   x = 20 grams   correct answer 20 grams
<result>E</result>
A jeweler has a 20 gram ring that is 60% gold and 40% silver. He wants to melt it down and
add enough gold to make it 80% gold. How many grams of gold should be added?