A stone is placed in a beaker of water. The initial volume of water is 30 cm3. After the stone is added, the volume increases to 60 cm3. What is the volume of the stone?

From the first beaker in the diagram, the initial volume of water is $30 \text{ cm}^3$.

$$V1 = 30 \text{ cm}^3$$

From the second beaker in the diagram, after the stone is added, the final volume of water is $60 \text{ cm}^3$.

$$V2 = 60 \text{ cm}^3$$

The volume of the stone is the difference between the final volume and the initial volume.

$$\text{Volume of the stone} = V2 - V1$$ $$\text{Volume of the stone} = 60 \text{ cm}^3 - 30 \text{ cm}^3$$ $$\text{Volume of the stone} = 30 \text{ cm}^3$$

Initial volume - V1 = $\boxed{\text{30 cm}^3}$
Final volume - V2 = $\boxed{\text{60 cm}^3}$
Volume of the stone = $\boxed{\text{30 cm}^3}$