The table gives data for the world population and the world urban population in billions...

The table gives data for the world population and the world urban population in billions. Let W(x) and U(x) denote functions describing the world population and world urban population, respectively, at time x.

a. Use the data in the table to sketch approximate graphs of y = W(x) and y = U(x).

b. Use W(x) and U(x) to describe two new functions representing the world nonurban population N(x) and S(x) the share of the world population that is urban as a percentage of the total world population. Use the data in the table to sketch approximate graphs of y = N(x) and y = S(x).