We have been given that a jeweler has 5 rings, each weighing 12 g, made of an alloy of 20% silver and 80% gold.
Upon melting all 5 rings, the weight of the material will be 12*5=60 grams.
We have been given that the alloy contains 20% silver and 80% gold. Further, let us assume that x grams of silver are added to the melted material so that it has 64% gold and 36% silver.
Therefore, we can set up an equation:
Therefore, we get an equation:
Therefore, 15 grams of silver must be added to the melted material in order to reduce the gold content to 64%.