The density of a substance is the mass per unit volume, usually expressed as grams per milliliter. We know what the mass of the solid is (123.4 grams), so we need to figure out what its volume is. We can determine this by subtracting the volume of the water from the total volume of the solution of the solid dissolved in water. This gives 62.7 mL - 48.4 mL = 14.3 mL. Now divide the mass of the solid by this volume: 123.4 g/14.3 mL = 8.63 g/mL.
The density of the solid is 8.63 g/mL.
volume of solid= vol. of water and solid - vol of water
62.7- 48.4= 14.3 ml
1 ml= 1 cm^3
density= mass/ volume
mass per vol= 123.4/14.3=8.629307g/cm^3