Final answer:
To estimate the population of the town in 2020 after a 20% growth in five years, divide 20% by 5 to get 4% per year. Multiply the current population by the growth factor of 1.04 to estimate the population in 2020.
Step-by-step explanation:
To estimate the population of the town in 2020, we need to find the population after a 20% growth over five years.
First, calculate the population growth rate per year by dividing 20% by 5, which is 4% per year.
Then, calculate the population in 2020 by multiplying the current population (18,978) by the growth factor of 1.04 (1 + 4% expressed as a decimal). The estimated population in 2020 is approximately 19,475.