A dark grey rock has a mass of 80 grams. When dropped in water, it makes the water level rise from 70 mL to 90 mL. What is the density of the rock?

I don't remember how to label it, but it is 20.

Explanation:

The answer is 20 because once you dat the rock in the water, that is how much it changed.

The density of the rock is 4 g/mL

Explanation:

The formula to be used here is that of density as shown below

Density = mass : volume

From the question, the mass of the dark grey rock is 80 grams

The volume of the rock is 90 mL - 70 mL = 20 mL (the reason for subtracting is because we concerned about the volume of the rock and not the volume of the water, thus when the rock caused a rise in the volume of the water, that "rise" is the volume of the rock.

Density = 80 : 20

Density = 4 g/mL

The density of the rock is 4 g/mL