To begin, we are told from the question that the rate of increase of the population of the country is proportional to the number of people presently living in the country.
Let make N represent the population of the country at any given time t and No as the initial population.
where k is the constant of proportionality.
For t=0, N = No
For t = 2 yrs, N = 2No
Substitute these values into (1)
k = 0.347
Therefore (1) becomes
For t = 3 yrs, N = 20,000
Substitute these values into (2)
No = 7062
Therefore the number of people initially living in the country is 7062