# The mass of a piece of paper is $0.02\;g$ and the mass of a solid substance along with the same piece of paper is $20.036\;g$. If the volume of the solid is $2.16\;cm^3$ its density to the proper number of significant digits will be

$(a)\;9.27 \;g\;cm^{-3}\\ (b)\;43.24 \;g\;cm^{-3} \\(c)\;9.267 \;g\;cm^{-3} \\(d)\;9.3 \;g\;cm^{-3}$

Mass of solid $= 20.036 -0.02$
$\qquad= 20.016 \;g=> 20.02\;g$
Density $= \large\frac{20.02}{2.16}$
$\qquad= 9.268=> 9.27$
Hence a is the correct answer.