Examples 11/19
1. (Why Exponential) Let’s make the optimal assumption: people will give birth to 2
children when they are 25 and they will die at the age of 75. Calculate the number of
living offsprings of a guy, say Jack, from the year when he is 25.
2. (Chinese One-child Policy) After introducing One-child Policy in 1978, the birth rate
of China decreased from 3% in 1980 to 1.8% in 2008. The population was 981 million
in 1980 and 1325 million in 2008. Let’s assume the death rate is always 1%.
(a) What was the population in 2008 if the One-child Policy were not applied?
(b) Starting from the 1325 million population in 2008. Estimate the population in
2100 for birth rates of 3% and 1.8% respectively.