# Gold with a mass of 400 g was alloyed with copper with a mass of 45 g. Determine the fineness of the resulting gold alloy.

The term “test” for precious metal alloys means the content of the precious metal in 1000 grams of the alloy. For example, the fineness of silver 925 indicates the presence in 1000 of the alloy only 925 of pure silver. The rest is other metals.

To solve our problem, we calculate the mass of the obtained alloy and calculate the sample through the simplest proportion.

m = 400 + 45 = 445 g is the mass of an alloy of gold with copper

Now let’s make the proportion:

400 g of gold is contained in 445 g of alloy, and

x g of gold is contained in 1000 g of alloy

X = (1000 * 400) / 445 = 898.9 g of gold in 1000 g of alloy. The fineness of the gold alloy is the same.

Answer: fineness of gold alloy 898.9

One of the components of a person's success in our time is receiving modern high-quality education, mastering the knowledge, skills and abilities necessary for life in society. A person today needs to study almost all his life, mastering everything new and new, acquiring the necessary professional qualities.