Question

Масса сплава меди и серебра равна 7,2 кг. Масса серебра составляет 80% массы меди. Сколько килограммов меди в сплаве? Помогите пожалуйста! Срочно! С решением и кр. Записью

Answer 1

80 : 100 * 7.2=5.76
7.2-5.76=1.44

Answer 2

Problem Analysis

We are given that the total mass of a copper and silver alloy is 7.2 kg, and the mass of silver is 80% of the mass of copper. We need to find the mass of copper in the alloy.

Solution

Let's assume the mass of copper in the alloy is x kg. Since the mass of silver is 80% of the mass of copper, the mass of silver can be calculated as 80% of x kg, which is 0.8x kg.

According to the problem, the total mass of the alloy is 7.2 kg. Therefore, the sum of the masses of copper and silver should be equal to 7.2 kg:

x + 0.8x = 7.2

Simplifying the equation:

1.8x = 7.2

Dividing both sides of the equation by 1.8:

x = 7.2 / 1.8

Evaluating the expression:

x = 4

Therefore, the mass of copper in the alloy is 4 kg.

Answer

The mass of copper in the alloy is 4 kg.

Solution Verification

To verify the solution, we can substitute the value of x back into the equation and check if it satisfies the given conditions.

The mass of silver can be calculated as 80% of 4 kg, which is 3.2 kg. The sum of the masses of copper and silver is 4 kg + 3.2 kg = 7.2 kg, which matches the total mass of the alloy as given in the problem.

Therefore, the solution is verified.