Solve the following numerical problem.
The masses of five marbles are 50 g, 55 g, 60 g, 65 g, and 70 g. Find their average mass.
Name and define the S.I. unit of time. How is it related to (i) minute (ii) hour, (iii) day, and (iv) year?
Define one kilogram, the S.I. unit of mass. How is it related to (i) quintal (ii) metric tonne and (iii) gram.