# To an alloy ingot weighing 400 kg containing 15% copper, 25 kg of copper was added.

To an alloy ingot weighing 400 kg containing 15% copper, 25 kg of copper was added. what is the percentage of copper in the new ingot?

We have an alloy weighing 400 kg. The concentration of copper in the alloy is 15%. Another 25 kg of copper was added to the alloy. Let’s find the concentration of copper in the new alloy.

First, find the mass of copper in the alloy before adding the metal.

400 * 0.15 = 60 kg of copper in the alloy initially.

After adding the copper mass became:

60 + 25 = 85 kg – the mass of copper after adding.

After the addition, the mass of the alloy became:

400 + 25 = 425 kg.

Now let’s find the new concentration of copper in the alloy:

85: 425 = 0.2 = 20%.

Answer: The concentration of copper in the alloy after the addition became 20%.

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