In 56 kg of alloy, copper and zinc are in a ratio of 2.5: 4.5. How many kg of copper is there less in this alloy?

It is known that the ratio of copper to zinc in the alloy is 2.5: 4.5. Let’s find how many parts of the metal are included in the alloy:
2.5 + 4.5 = 7 (parts) – metals make up the entire alloy.
The total weight of the alloy is 56 kilograms. Let’s find how many kilograms are in 1 part of the alloy:
56: 7 = 8 (kilogram) – metal accounts for 1 part of the alloy.
Let’s find the total mass of copper in the resulting alloy:
2.5 * 8 = 20 (kilogram) – copper in the alloy.
Let’s find the total mass of zinc in the alloy:
Method 1:
4.5 * 8 = 36 (kilogram) – zinc alloy.
Method 2:
56 – 20 = 36 (kilogram) – zinc alloy.
Let’s find how many kilograms of copper in the alloy was less than zinc:
36 – 20 = 16 (kilogram) – the difference.
Answer: less by 16 kilograms.