# Determine the density of the rock using correct significant digits. The mass of the rock is 25.69 g?

$\text{Density, "rho="Mass"/"Volume} = 2.6 \cdot g \cdot m {L}^{-} 1$
And thus ${\rho}_{\text{rock}} = \frac{25.69 \cdot g}{\left(40 - 30\right) \cdot m L}$ $=$ $2.6 \cdot g \cdot m {L}^{-} 1$