From Archimedes' principle, when an object with known mass and volume is placed on a container also containing liquid mass and volume, there will be volume displacement. The amount of volume displaced is equal to the volume of the object. The solution is as follows:
Volume displaced = 24.7 mL - 20 mL = 4.7 mL
Density = Mass/Volume = 36.7 g/4.7 mL = 7.81 g/mL