One alloy contains 30% copper and the other 70% copper. How much of each alloy should

| March 8, 2021 | education

One alloy contains 30% copper and the other 70% copper. How much of each alloy should you take to get 100kg of alloy containing 40% copper?

Let’s say that x kg was taken for the first alloy.

Since it turned out 100 kg of alloy, it means that the second alloy was taken

100 – x kg.

In the first alloy, the copper content is 30%, which means that the mass of copper in it is x * 30: 100 = 0.3 * x kg.

In the second alloy, the copper content is 70%, which means that the mass of copper in it is (100 – x) * 70: 100 = 70 – 0.7 * x kg.

In the resulting alloy, the mass of which is 100 kg, the copper content is 40%, which means that the mass of copper is 100 * 40: 100 = 40 kg.

Let’s compose and solve the equation:

0.3 * x + 70 – 0.7 * x = 40,

0.4 * x = 30,

x = 75 (kg) is the mass of the first alloy.

100 – 75 = 25 (kg) – the mass of the second alloy.



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