We have the next function
a)
We substitute t=0 in the function
6.1 billion in the year 2000
b)
In 2200, t=200
We substitute the value of t in the function given
11.79 billion in the year 2200
c)
The graph of the function is
d)
The size of the world population seems to approach is 12 billion of people
ANSWER
a) 6.1 billion in the year 2000
b) 11.79 billion in the year 2200
c) see the graph above
d) 12 billion of people