# Prompt

(Population projection) The U.S. Census Bureau projects population based on the

following assumptions:

■ One birth every 7 seconds

■ One death every 13 seconds

■ One new immigrant every 45 seconds

Write a program to display the population for each of the next five years. Assume the

current population is 312,032,486 and one year has 365 days. Hint: In Java, if two

integers perform division, the result is an integer. The fractional part is truncated. For

example, 5 / 4 is 1 (not 1.25) and 10 / 4 is 2 (not 2.5). To get an accurate result with

the fractional part, one of the values involved in the division must be a number with a

decimal point. For example, 5.0 / 4 is 1.25 and 10 / 4.0 is 2.5.

# Answer

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public class Population_Project { public static void main(String[] args) { System.out.println("current population is 312032486"); //Store current population as variable intPop double intPop = 312032486; //add one birth every 7 seconds; subtract one death every 13 seconds; add one immigrant every 45 seconds. // 365 days = 1 year | 1 day = 24 hours | 1 hour = 60 minutes | 1 minute = 60 seconds // 7 seconds = 1 birth | 13 seconds = 1 death | 45 seconds = 1 immigrant // 365days * 24hours * 60minutes * 60seconds = 31536000 seconds double numberOfSecondsInYear = 31536000; //After 1 year, number of births (7 seconds = 1 birth | plus) double birthsPerYear = numberOfSecondsInYear / 7; System.out.println("brithsPerYear: " + birthsPerYear); //After 1 year, number of deaths (13 seconds = 1 death | minus) double deathsPerYear = numberOfSecondsInYear / 13; System.out.println("deathsPerYear: " + deathsPerYear); //After 1 year, number of immigrants (45 seconds = 1 immigrant | plus) double immigrantsPerYear = numberOfSecondsInYear / 45; System.out.println("immigrantsPerYear: " + immigrantsPerYear); //Rate per year double ratePerYear = birthsPerYear - deathsPerYear + immigrantsPerYear; System.out.println("ratePerYear: " + ratePerYear); System.out.println("End of year 1 the population is " + (int)(intPop + (1 * ratePerYear))); System.out.println("End of year 2 the population is " + (int)(intPop + (2 * ratePerYear))); System.out.println("End of year 3 the population is " + (int)(intPop + (3 * ratePerYear))); System.out.println("End of year 4 the population is " + (int)(intPop + (4 * ratePerYear))); System.out.println("End of year 5 the population is " + (int)(intPop + (5 * ratePerYear))); } } |