The mass of a box measured by a grocer’s balane is 2.3 kg. Two gold pieces of masses 20.15 g and 20.17 g are added to the box. The total mass of the box is

Here, mass of the box, m = 2.3 kg

Mass of one gold piece, ${\mathrm{m}}_1=20.15\mathrm{g}=0.02015\mathrm{kg}$

Mass of other gold piece, ${\mathrm{m}}_2=20.17\mathrm{g}=0.02017\mathrm{kg}$

 $\therefore$Total mass = $\mathrm{m}+{\mathrm{m}}_1+{\mathrm{m}}_2$

= 2.3 kg+ 0.02015 kg +0.02017 kg

= 2.34032 kg

As the result is correct only up to one place of decimal, therefore, on rounding off, we get

Total mass = 2.3 kg