Question

Кусок сплава меди с оловом весом 12 кг содержит 45% меди . Сколько число олова надо приобрести к этому куску чтоб получился новый сплав имел 40% меди?

Answer 1

Calculation of the Amount of Lead Needed

To calculate the amount of lead needed to create a new alloy with 40% copper, we can use the following equation:

Copper in the original alloy + Copper in the lead = Copper in the new alloy

Given that the original alloy weighs 12 kg and contains 45% copper, we can calculate the amount of copper in the original alloy:

Copper in the original alloy = 12 kg * 45% = 5.4 kg

Let's assume the amount of lead needed is x kg. Since the new alloy is required to have 40% copper, we can set up the following equation:

5.4 kg + 0 kg = (12 kg + x kg) * 40%

Simplifying the equation:

5.4 kg = (12 kg + x kg) * 0.4

Now, we can solve for x:

5.4 kg = 0.4 * (12 kg + x kg)

5.4 kg = 4.8 kg + 0.4x kg

Subtracting 4.8 kg from both sides:

0.6 kg = 0.4x kg

Dividing both sides by 0.4 kg:

1.5 kg = x kg

Therefore, you would need to acquire 1.5 kg of lead to create a new alloy with 40% copper.

Please note that the calculations above are based on the given information and assumptions.