# Numericals on Density & Relative Density Class 9

This post is on **Numericals on Density & Relative Density** for Class 9.

**Formulas Used**

Mass = Volume x density

Volume = mass/density

Density = mass/volume

Relative density RD of a substance = mass of the substance/mass of water of the same volume

Relative density RD of a substance = density of the substance/density of water

**Numericals on density and relative density [for class 9] – solved**

1] Relative density of gold is 19.3. The density of water is 10^{3}kg/m^{3}. What is the density of gold in kg/m^{3}?

**Solution:**

Given:

The relative density of gold is 19.3.

The density of water is 10^{3} kg/m^{3}

Relative density of gold = density of gold/density of water

=> density of gold = Relative density of gold x density of water

So, thedensity of gold = 19.3 x 10^{3}kg/m^{3}

2] Mass of 0.025 m^{3} of Aluminium is 67 kg. Calculate the density of Aluminium.

**Solution:**

Given,

Mass of Aluminium = 67 kg

Volume of Aluminium = 0.025 m^{3}

So, the Density of Aluminium = mass/volume = 67/0.025 = 2680 kg/m

^{3}