The number of people expected to have a disease in t years is given by
y(t) = a.3^(t/a) (i) if now (year 2016) the number of people having the disease is 1000, find the value of a.
(ii) how many people are expected to have the disease in five years?
(iii) when are 100,000 people expected to have the disease?
(iv) how fast is the number of people with the disease expected to grow now and ten years from now?