Problem $7\mathrm{.}1$

Answer the following questions using the "world" database, available for download from

OA $7\mathrm{.}2.$ Present your SQL queries and$/$or processes that you used to derive the answers.

a$.$ How many countries became independent in the twentieth century?

b$.$ How many people in the world are expected to live for $75$ years or more?

c$.$ List the $10$ most populated countries in the world with their population as percentage of

the world population. $[$Hint: You can first find the population of the world and then use it

for percentage for countries, so something like: select Population$/5000000000$ from

Country $....]$

d$.$ List the top $10$ countries with the highest population density. $[$Hint: For population

density, you can try something like: select Population$/$SurfaceArea from Country

where $....]$