# What is the mass density of a rock of mass 300 g that has an apparent mass of 200 g in water?

Aug 25, 2016

The density is 3.00 grams/ ml

#### Explanation:

The rock weighs 100 grams less in water than it does in air

$300 g - 200 g = 100 g$

The density of water is $1 \frac{g}{1} m l$

so 100 gram difference means 100 ml of water were displaced.

$\frac{100 \frac{g}{1}}{l \frac{g}{1} m l}$ xx ( 1 ml/ 1 g) / (1 ml / 1 g ) = 100 ml

so the volume of the rock is 100 ml.

Density = Mass / Volume.

Density = $300 \frac{g}{100} m l$ = 3 g/ ml