(a) the total mass of the box,
(b) the difference in the masses of the pieces to correct significant figures?
Answer:
According to the question, mass of the box is 2.30 kg and the mass of the first gold piece is 20.15 g. Also, the mass of the second gold piece is 20.17 g.
Then, the total mass = 2.300 + 0.2015 + 0.2017
= 2.7032 kg
Since the least number of decimal places is 1, the total mass = 2.7 kg.
The mass difference of pieces = 20.17 – 20.15 = 0.02 g
Since the least number of decimal places is 2, the total mass difference= 0.02 g.