A box contains a mixture of small copper spheres and small lead spheres. The total volume of both metals is measured by the displacement of water to be 426 cm^{3} and the total mass is 4.31 kg .

What percentage of the spheres are copper?

We are being asked to calculate the **percentage of copper spheres in the mixture**.

We are given: total mass = 4.31 kg and total volume = 426 cm^{3}

**This mean:**

mass_{Cu} + mass_{Pb} = 4.31 kg

Volume_{Cu} + Volume_{Pb} = 426 cm^{3}

We can relate mass and volume using **density**.

Recall: **Density** represents the mass of an object or compound within a given volume.

$\overline{){\mathbf{Density}}{\mathbf{\left(}}{\mathbf{d}}{\mathbf{\right)}}{\mathbf{}}{\mathbf{=}}{\mathbf{}}\frac{\mathbf{mass}\mathbf{}\mathbf{\left(}\mathbf{m}\mathbf{\right)}}{\mathbf{Volume}\mathbf{}\mathbf{\left(}\mathbf{V}\mathbf{\right)}}}$

Density