The mass of a box measured by a grocer's balacne is 2.3 kg. Two gold pieces of masses 20.15 g and 20.17 g are added to the box. What is (a) the total mass of the box. (b) the difference in the masses of the pieces to correct significant figures?

Answer

a. 2.3 kg b. 0.020 g

Explanation

`D=m//V=4.63//1.1=1.2090gcm^(-3)=4.2gcm^(-3)` (`:.` V has only 2 significant digits)