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

After adding the gold pieces, Total mass=2.3+0.02015+0.02017 kg.

According to the rules of arithmetic operations of significant figures, It is rounded off to one decimal point.

So, total mass=2.3kg.