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?

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

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.