The alloy weighing 800 g contains 60% zinc. 200 g of zinc was added to the alloy and re-melted.

| June 26, 2021 | education

The alloy weighing 800 g contains 60% zinc. 200 g of zinc was added to the alloy and re-melted. What percentage of zinc is contained in the new alloy.

Let’s use a percentage.

The total mass of the alloy is 800 (g) or 100%, it contains x (g) or 60% zinc, which means:

800 (g) – 100%,

x (g) – 60%.

x (z) * 100% = 800 (z) * 60%.

x = 800 (g) * 60% / 100% = 800 (g) * 0.6 = 480 grams.

The original alloy contained 480 grams of zinc.

In this case, 200 grams of zinc was added to the alloy, therefore, the mass of zinc changed: 480 (g) + 200 (g) = 680 grams and the total mass of the alloy changed: 800 (g) + 200 (g) = 1000 grams.

The mass of the new alloy is 1000 (g) or 100%, the mass of zinc in the new alloy is 680 (g) or x%.

1000 (g) – 100%,

680 (g) – x%.

x% * 1000 (g) = 100% * 680 (g).

x = 68000/1000 = 68%.

Answer: 68% of zinc is contained in the new alloy.



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