On 1st November 2015 there were 4200 trees planted in a wood.
On 1st November 2016, only 3948 of these trees were still alive.
It is assumed that the number of trees still alive is given by
N = art
where N is the number of trees still alive t years after 1st November 2015.
It can be shown that a = 4200.
Find the value of r
(2 marks)
