(Population projection) Python Question

Question

The US 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 312032486 and one year has 365 days.

Answer 1

Step 1 shows an easy-to-read example of what is actually going on--translating the ratios into minute, hour, daily, and ultimately yearly figures and then showing the yearly change over the course of 5 years.

def pop(n):

one_min = 60/n -- n represents the number of seconds that either a birth, death, or immigration occurs

hour = one_min * 60

day = hour * 24

year = round(day * 365)

return year

births = pop(7) #1 in 7 seconds

death = pop(13) #1 in 13 seconds

immigrant =pop(45) #1 in 45 seconds

current_pop = 312032486

for i in range(5):

current_pop += births - death + immigrant

print(current_pop)

Step 2 is a 'quicker' version of Step 1:

demo = lambda n: round(60/n * 60 *24 *365)

a = demo(7) #births

b = demo(13) #deaths

c = demo(45) #immigrants

for i in range(5):

current_pop += a - b + c

print(current_pop) #check

Answer 2

Hello Richard I would do something along the following lines since birth, death and new immigrants rates are someone what of a constant.

def getNextYearPopulation(currentPop) :

return currentPop + BIRTHS_PER_YEAR + NEW_IMMIGRANTS_PER_YEAR - DEATHS_PER_YEAR

# secondsInAYear = seconds in a minute * minutes in an hour * hours in a day * days in a year or 31536000

SECONDS_IN_A_YEAR = 60*60*24*365

# One birth every 7 seconds

BIRTHS_PER_YEAR = SECONDS_IN_A_YEAR//7

# One death every 13 seconds

DEATHS_PER_YEAR = SECONDS_IN_A_YEAR//13

# One new immigrant every 45 seconds

NEW_IMMIGRANTS_PER_YEAR = SECONDS_IN_A_YEAR//13

print("SECONDS_IN_A_YEAR", SECONDS_IN_A_YEAR)

print("BIRTHS_PER_YEAR", BIRTHS_PER_YEAR)

print("DEATHS_PER_YEAR", DEATHS_PER_YEAR)

print("NEW_IMMIGRANTS_PER_YEAR", NEW_IMMIGRANTS_PER_YEAR)

# current population

population = 312032486

for x in range(1,6):

population = getNextYearPopulation(population)

print("population for year", x, "is ", population)