It's a math question
Answers (1)
The question is, I guess, "How many years n will it take for a population P to increase by continuous growth at a given rate p from a not otherwise specified number of individuals to four times that number?"
4P = P * (1 + p/100)^n
4P/P = (1 + p/100)^n ## logarithmize
ln(4P/P) = ln(1 + p/100)^n ## ln a^x = x * ln a
ln 4 = n * ln(1 + p/100)
ln 4 / ln(1 + p/100) = n
ln 4 / ln 1.028 = 50.2004...
Quadrupling the citizenship of the particular country at a 'constant' compound growth rate of 2.8% per year will take more than half a century.
Let's assume a small country, where on January 1st 2000 lived 1,000,000 people:
(Checking the result by iteration is a job for a 'ByteCruncher')
>>>
After 1 year, the population is: 1028000.00
After 2 years, the population is: 1056784.00
After 3 years, the population is: 1086373.95
After 4 years, the population is: 1116792.42
After 5 years, the population is: 1148062.61
After 6 years, the population is: 1180208.36
After 7 years, the population is: 1213254.20
After 8 years, the population is: 1247225.32
After 9 years, the population is: 1282147.62
After 10 years, the population is: 1318047.76
After 11 years, the population is: 1354953.09
After 12 years, the population is: 1392891.78
After 13 years, the population is: 1431892.75
After 14 years, the population is: 1471985.75
After 15 years, the population is: 1513201.35
After 16 years, the population is: 1555570.99
After 17 years, the population is: 1599126.97
After 18 years, the population is: 1643902.53
After 19 years, the population is: 1689931.80
After 20 years, the population is: 1737249.89
After 21 years, the population is: 1785892.89
After 22 years, the population is: 1835897.89
After 23 years, the population is: 1887303.03
After 24 years, the population is: 1940147.51
After 25 years, the population is: 1994471.65
After 26 years, the population is: 2050316.85
After 27 years, the population is: 2107725.72
After 28 years, the population is: 2166742.04
After 29 years, the population is: 2227410.82
After 30 years, the population is: 2289778.32
After 31 years, the population is: 2353892.12
After 32 years, the population is: 2419801.10
After 33 years, the population is: 2487555.53
After 34 years, the population is: 2557207.08
After 35 years, the population is: 2628808.88
After 36 years, the population is: 2702415.53
After 37 years, the population is: 2778083.16
After 38 years, the population is: 2855869.49
After 39 years, the population is: 2935833.84
After 40 years, the population is: 3018037.18
After 41 years, the population is: 3102542.23
After 42 years, the population is: 3189413.41
After 43 years, the population is: 3278716.98
After 44 years, the population is: 3370521.06
After 45 years, the population is: 3464895.65
After 46 years, the population is: 3561912.73
After 47 years, the population is: 3661646.28
After 48 years, the population is: 3764172.38
After 49 years, the population is: 3869569.21
After 50 years, the population is: 3977917.14
After 51 years, the population is: 4089298.82
>>>
In the middle of March 2050 the population will surpass 4,000,000 people.
0.2 years are 2.4 [= 12 * 0.2] months or 73 [= 365 * 0.2] days.