57.9 g of gold has a volume of 3 cm³ what is the density of gold in g/ centimeters cubed

The answer is:  " 20 g/cm³ " .

Density = mass (g) per unit volume (cm³) ; 

or:  D = m / v ; 

D  =  57.9 g / 3 cm³   =  (57.9 / 3)  g / cm³  = 19.3 g / cm³ ;
                                                      → round to "1 significant figure; 
                                                     to get:  20 g / cm³