Question

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 and the difference in the masses of the pieces to correct significant figures?

• A. 2.34 kg, 0 g
• B. 2.3 kg, 0.02 g
• C. 2.34 kg, 0.02 g
• D. 2.3 kg, 0 g

Answer 1

Answer: (B)

Here, mass of the box, $m =2.3 kg$
Mass of one gold piece, $m _{1}=20.15 g =0.02015 kg$
Mass of other gold piece, $m _{2}=20.17 g =0.02017 kg$
$\therefore$ Total mass $= m + m _{1}+ m _{2}=2.3 kg +0.02015 kg +0.02017 kg =2.34032 kg$
As the result is correct only upto one place of decimal, therefore, on rounding off, we get Total mass $=2.3 kg$