Answer:
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
