**Solution:** If food resources are adequately available to individuals in a population, it grows exponentially. To estimate the exponential growth, we can use the integral form of exponential growth equation, which is as follows:

———-equation (1)

Where N_{t} is the population density after ‘t’ time

N_{o} is the population density at time zero

e is the base of natural logarithm = 2.71828

r is the intrinsic rate of natural increase

Let the current population density be ‘x’

∴ The population density after two years will be 2x and t given is 3 years

Substituting these values in equation (1)

Therefore, the intrinsic rate of natural increase of the population is 0.2311