In a stationery store, packages of paper are stored in stacks of 60 packages. Each package contains 500 sheets of paper and each sheet of paper has a thickness of $0.1 \mathrm{~mm}$. Ignoring the thickness of the paper used to wrap the packages, we can state that the height of a stack of 60 packages is approximately equal to the height of:
(a) an adult person;
(d) a 10-story building;
(b) a one-year-old baby;
(e) a classroom.
(c) a common table;
The correct option is (e).

Since the thickness of each sheet is $0.1 \mathrm{~mm}$, the height of a package with 500 sheets is $500 \times 0.1 \mathrm{~mm}=50 \mathrm{~mm}$. Therefore, the height of each stack will be $60 \times 50 \mathrm{~mm}=3000 \mathrm{~mm}$ $=3 \mathrm{~m}$, approximately the height of a classroom.