Question

An alloy of brass is composed of 84.6% copper, 5.20% tin, 6.70% lead, and zinc. What is the number of pounds of zinc required to make 520.0 pounds of alloy?

Answers

GPT 3.5
The percentage of zinc in the alloy is the difference between 100% and the sum of the other percentages: 100% - 84.6% - 5.20% - 6.70% = 3.50%.
The weight of the zinc required is 3.50% of 520.0 pounds: 3.50% * 520.0 pounds = 0.035 * 520.0 pounds = 18.2 pounds. Answer: \boxed{18.2}.