# What is the density of a rock that has a mass of 140 grams, and raises the water level from 25 mL to 57 mL?

Oct 6, 2016

$\rho , \text{ density}$ $=$ $\text{Mass"/"Volume}$

#### Explanation:

We know (i) the mass of the rock, and (ii) also its volume because it displaced $32 \cdot m L$ of water. And thus.....

Here $\rho$ $=$ $\frac{140 \cdot g}{\left(57 - 25\right) \cdot m L}$ $=$ $\frac{140 \cdot g}{32 \cdot m L}$ $\cong$ $4.4 \cdot g \cdot m {L}^{-} 1$.