There is one more value of x between 2 and 3, multiplied by 5, so 5 is the net change between the two variables.
Answer:
A - 8:1
Step-by-step explanation:
2/5:1/20
cross multiply
40:5
8:1
3.5 kg:800g
3500g:800g
35g:8g
Answer:
a) 
b) 6.84 million
c) 2028.52
d) 47 years
Step-by-step explanation:
a)Here we know standard exponential growth rate is

In this put t=0 and a(t)=6.27 million
thus we get a = 6.27 million
now 
this is equal to(in 2012)=
b)Put t = 6
we get

=6.84 million
c) 
take log both sides
we get 16.52 years
d) 
take log both sides we get 47 years to get double the current population.
The sides could be 1,14 or 2,7