Question 2.8: A student determines that the mass of a 20.0-mL sample of ol......

To calculate density, we substitute the given mass and volume values into the defining formula for density.
$\quad\quad\quad Density =\frac{mass}{volume}=\frac{18.4  g}{20.0  mL}=0.92  \frac{g}{mL}\quad\quad (calculator  answer)\\\quad\quad\quad\quad\quad\quad\quad\quad\quad\quad\quad\quad\quad\quad\quad= 0.920  \frac{g}{mL}\quad\quad (correct  anwer)$
Because both input numbers contain three significant figures, the density is specified to three significant figures.