Final answer:
To calculate the density of each sample, divide the mass by the volume. Samples B and C have the same density of 3 g/ml.
Step-by-step explanation:
The density of a substance is defined as its mass divided by its volume. To identify which samples have the same density, we can calculate the density for each sample by dividing its mass by its volume.
For sample A, which has a mass of 80 grams and a volume of 20 milliliters, its density would be 80 g / 20 ml = 4 g/ml.
For sample B, which has a mass of 12 grams and a volume of 4 milliliters, its density would be 12 g / 4 ml = 3 g/ml.
For sample C, which has a mass of 33 grams and a volume of 11 milliliters, its density would be 33 g / 11 ml = 3 g/ml.
Therefore, samples B and C have the same density of 3 g/ml.