Final answer:
The mass of water displaced by the submerged rock is 198 g, which is also the volume of the rock (in cm³) since the density of water is 1 g/cm³. Consequently, the rock's average density is calculated to be 2.727 g/cm³, which aligns with the density of granite.
Step-by-step explanation:
When a rock with a mass of 540 g is submerged in water and exhibits an apparent mass of 342 g, the mass of water displaced is equal to the difference between its mass in air and its apparent mass when submerged, which would be 540 g - 342 g = 198 g.
The volume of the rock can be determined from the mass of displaced water, given that the density of water is 1 g/cm3, hence the volume is also 198 cm3.
The average density of the rock is then the mass of the rock divided by its volume, which is 540 g / 198 cm3 = 2.727 g/cm3.
This density is consistent with the density of granite.