Answer:
9.64g/mL
Step-by-step explanation:
Given parameters: 
Mass of the metal = 106g 
Volume of cylinder = 50mL 
Volume difference = 31mL - 20mL = 11mL 
Unknown: 
Density of the metal = ? 
Solution: 
To find the density of the metal, we use;
 Density = 
 
 
 Density = 
 = 9.64g/mL
 = 9.64g/mL