1. **State the problem:** We are asked to find the volume of one red marble in cm³ given measurements involving marbles placed in a water overflow vessel. 2. **Understand the given data:** - Initially, water level is at 100 mL. - After placing 2 red marbles and 2 green marbles, water is still at 100 mL. - After adding 3 more green marbles (so total 2 red + 5 green), water level rises to 160 mL. 3. **Analyze the information:** - Since placing 2 red and 2 green marbles keeps water at 100 mL, it means those marbles are already submerged or there is no change in water volume yet (likely water was adjusted after putting marbles). - After adding 3 more green marbles, water volume increases by 60 mL (from 100 to 160 mL). 4. **Assumption about the marbles:** - All red marbles are identical. - All green marbles are identical. 5. **Let variables represent unknowns:** - Let $V_r$ be the volume of one red marble (cm³). - Let $V_g$ be the volume of one green marble (cm³). 6. **Setting up the equation:** - The additional 3 green marbles cause the water to rise by 60 mL. - Therefore, $$3 \times V_g = 60$$ which implies $$V_g = \frac{60}{3} = 20$$ 7. **Use initial information:** - Since the water level did not rise after placing the first 2 red + 2 green marbles (still 100 mL), it suggests the initial water volume already accounts for those marbles submerged. Hence, no displacement from initial 100 mL due to them. 8. **From this, the volume of each red marble cannot be directly determined from water levels alone because initial placement doesn’t change water level. It implies the initial water level was adjusted to 100 mL considering those 4 marbles. 9. **Given the problem states to find volume of 1 red marble:** - We only have data for green marbles volume: 20 cm³ per green marble. - The problem does not provide a volume change due only to red marbles. 10. **Conclusion:** - Without additional information about volume changes caused solely by red marbles, or differences in displacement, the volume of one red marble cannot be determined from the data provided. Final answer: - Volume of one red marble cannot be determined based on given water level data. **Note:** If the initial 2 red + 2 green marbles already displaced water, then the total displaced volume for them is zero since water level remained at 100 mL after their addition implying the volume measurement for red marbles is not deducible.