# The alloy consists of silver, copper and gold. The ratio of the values is 2: 1: 7, respectively.

**The alloy consists of silver, copper and gold. The ratio of the values is 2: 1: 7, respectively. How many grams of each metal is contained in 640 g of the alloy?**

1. Let’s find how many parts are in the alloy:

2 + 1 + 7 = 10.

2. Find how much one part weighs.

640: 10 = 64.

3. Let’s find how many grams of each metal is included in the alloy, if the ratio of silver, copper and gold is 2: 1: 7.

4. Find the mass of silver, knowing that it is 2 parts.

64 x 2 = 128 g.

5. Find the mass of copper (1 part) – 64 g.

6. Find the mass of gold (7 parts):

64 x 7 = 448 g.

128 g + 64 g + 448 g = 640 g.

Second way.

Let us denote the mass of the metal by x.

2 x – weight of silver.

x is the mass of copper.

7 x is the mass of gold.

Let’s make an equation.

2x + x + 7x = 640.

10x = 640,

x = 640: 10,

x = 64.

64 x 2 = 128.

64 x 7 = 448.

Answer: 64 g; 128 g; 448 BC