Let's assume that every child has 2 parents. p=2c
Let's define total of childless internet users as m.

((m + p)/(m + p)) x 2.8 = c = p/2

(m + p)/(m + p) = p/1.4

m+p = p(m+p)/1.4

1.4(m+p) = p(m+p)

p=1.4, c=2.8, m is undefined. This is the only solution that fits the text. Of course, since it is physically impossible to have 1.4 parents and 2.8 children we know that solution does not exist. For starters my 3 year old internet user has two internet-using parents.