Karen measures the initial volume of water as 12.5 mL. She then adds a 2.3 gram rubber stopper and the volume rises to 20.8 mL. What is the volume of Karen's rubber stopper?

The volume of the rubber stopper is 8.3 mL.

Explanation:

because the initial volume of the water was 12.5 mL and the new volume was 20.8 mL. So you subtract the 20.8 minus 12.5 and you get 8.3 mL.

its "The volume of the rubber stopper is 8.3 mL."

i'd say that the moon rock is about 2.2 billion years old.