The alloy consists of 0.4 m3 copper and 714 kg zinc. What is the density of the alloy, if we assume that the volume of the alloy

The alloy consists of 0.4 m3 copper and 714 kg zinc. What is the density of the alloy, if we assume that the volume of the alloy is equal to the sum of the volumes of its constituent parts? The density of copper is 8900 kg / m3, the density of zinc is 7100 kg / m3.

ρ = m / V
ρ alloy = (m₁ + m₂) / (V₁ + V₂)
ρ₁ = 8390 kg / m ^ 3 copper
V₁ = 0.4 m ^ 3 – volume of copper
m₁ = ρ₁ * V₁ = 8390 * 0.4 = 3356 kg
ρ₂ = 6920 kg / m ^ 3 zinc
m₂ = 714 kg
V₂ = m₂ / ρ₂ = 714/6920 = 0.1 m ^ 3 volume of zinc
ρ alloy = (3356 + 714) / (0.4 + 0.1) = 8140 kg / m ^ 3
Answer: 8140 kg / m ^ 3