# What is the density of a 45 g object that when placed into 25 mL of the water the water rises to 40 mL?

$\rho \text{, density}$ $=$ $\text{Mass"/"Volume}$ $\cong 3 \cdot g \cdot m {L}^{-} 1$
Clearly, the object has displaced $15 \cdot m L$ of water, and thus has a volume of $15 \cdot m L$.
$\rho \text{, density}$ $=$ $\frac{45 \cdot g}{15 \cdot m L}$ =??*g*mL^-1.