Mixture Problem A jeweler has five rings, each weigh - ing 18 g, made of an alloy of 10% silver and 90% gold. She decides to melt down the rings and add enough silver to reduce the gold content to 75%. How much silver should she add?

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Chemistry

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5 January, 21:39

Mixture Problem A jeweler has five rings, each weigh - ing 18 g, made of an alloy of 10% silver and 90% gold. She decides to melt down the rings and add enough silver to reduce the gold content to 75%. How much silver should she add?

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Isaiah Bush · Answer 1

Total weight of 5 rings

= 18 x 5

= 90 g

silver = 10% of 90 g

= 9 g

gold = 81 g

Let silver added = x gm

Total weight = 90 + x

75% of (90+x) is gold

= 3/4 x (90+x) g is gold

So 3/4 x (90+x) = 81

(90+x) = 81 x 4 / 3

= 108

x = 18 g

silver to be added = 18g.