Brass is formed by mixing one volume part of zinc (density 7100 kg/m³) with two volume parts of copper (density 8900 kg/m³). The density of brass is

Correct answer: (b) 8300 kg/m³

Explanation

Take 1 m³ of zinc and 2 m³ of copper, 3 m³ of brass in all:

• mass of zinc = 1 × 7100 = 7100 kg
• mass of copper = 2 × 8900 = 17,800 kg
• total = 24,900 kg

Density of brass = 24,900 ÷ 3 = 8300 kg/m³.