SOLUTION: An alloy which weighs 118 kg is 10 percent silver. How much silver must be added to produce a metal that is 25 % silver?

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Question 555639: An alloy which weighs 118 kg is 10 percent silver. How much silver must be added to produce a metal that is 25 % silver?
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Let +x+ = kg of silver to be added
+.1%2A118+=+11.8+ kg of silver in 10% alloy
+%28+11.8+%2B+x+%29+%2F+%28+118+%2B+x+%29++=+.25+
+11.8+%2B+x+=+.25%2A%28+118+%2B+x+%29+
+11.8+%2B+x+=+29.5++%2B+.25x+
+.75x+=+29.5+-+11.8+
+.75x+=+17.7+
+x+=+23.6+
23.6 kg of silver must be added
check:
+%28+11.8+%2B+23.6+%29+%2F+%28+118+%2B+23.6+%29++=+.25+
+35.4+%2F+141.6+=+.25+
+35.4+=+.25%2A141.6+
+35.4+=+35.4+
OK