Brass is an alloy containing 60% copper and 40% zinc. How many kilograms of zinc

Brass is an alloy containing 60% copper and 40% zinc. How many kilograms of zinc do you need to add to 123 kilograms of copper to make brass?

Let’s write a short note:

60% = 123 kg of copper;

40% = x kg zinc.

Let’s make the proportion:

60: 123 = 40: x.

To find the extreme unknown term of the proportion, it is necessary to multiply the average terms and divide their product by the known extreme term.

x = 123 * 40: 60;

x = 82 (kg) – zinc.

Answer: for the alloy, you need to take 82 kg of zinc.