Posted by aaaa on .
British sterling silver is a coppersilver alloy that is 7.5% copper by weight. How many grams of pure copper and how many grams of British sterling silver should be used to prepare 170 grams of a coppersilver alloy that is 16% copper by weight?

algebra 
helper,
x = grams of copper
0.075x = value of copper
170  x = grams of silver
0.925(170  x) = value of silver (100  7.5 = 92.5)
.16(170) = value of mixture
0.075x + 0.925(170  x ) = 0.16(170)
Solve for x, grams of copper
(170  x) = grams of silver