In a graduated cylinder, the volume of water is 1.5 L. a piece of rock was thrown into it causing the level of water to rise to 2.5 L. What is the volume of the rock?

Answer 1

2.5 L - 1.5 L = 1.0 L = volume of the rock.

Look up and read about Archimedes Principle. You'll see why this is the answer.