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 are added to the box. What is the total mass of the box?

Here, mass of the box,m=2.3 kgMass of one gold piece,m=20.15 g=0.02015 kgMass of second gold piece,m2=20.17 g=0.02017 kgTotal mass=2.34032 kgAfter the decimal point there should be least or one significant figure. Therefore, answer should be 2.3 kg as we have to round off at one digit after decimal point.