Let y denote the percentage of the world population that is urban x years after 2014. According to data from the United Nations, 54 percent of the world’s population was urban in 2014, and projections show that this percentage will increase to 66 percent by 2050. Assume that y is a linear function of x since 2014.

(a) Determine y as a function of x.

(b) Interpret the slope as a rate of change.

(c) Find the percentage of the world’s population that is urban in 2020.

(d) Determine the year in which 72% of the world’s population will be urban.