What is the formula for density?

• A. Mass = density × volume
• B. Density = volume ÷ mass
• C. Density = mass ÷ volume
• D. Density × volume = mass

Answer: (C)

Density tells you how much matter is packed into a given amount of space. It is defined as the mass per unit volume, so the formula is density = mass ÷ volume. This direct definition shows how many grams (or kilograms) occupy each milliliter (or cubic meter), which is why you compute density by dividing mass by volume.

For example, if you have a mass of 200 g and a volume of 100 mL, the density is 200 g ÷ 100 mL = 2 g/mL. The statement mass = density × volume is mathematically the same relationship, just rearranged to solve for mass. Similarly, density × volume = mass is equivalent. The key point is that the quantity defining density itself is mass per volume, not volume per mass (which would be the reciprocal of density).