The alloy ingot is 28% copper, 56% iron, and the remaining 144g is nickel. What is the mass of the ingot?

1. Let’s find what percentage of the ingot mass is nickel.

100 – 56 – 28 = 16%.

2. Let’s make a proportion and find the mass of iron.

56 / x = 16/144

x = 144 * 56: 16

x = 504

144 * 0.16 = 23.04 gr.

3. Let’s make the proportion and find the mass of copper.

28 / x = 16/144

x = 144 * 28: 16

x = 252

4. Find the mass of the alloy ingot.

504 + 252 + 144 = 900 gr.

Answer: the weight of the ingot is 900 g.