The spam-farm architecture described in Section 5.4.1 suffers from
the problem that the target page has many links --- one to each supporting page.
To avoid that problem, the spammer could use the architecture shown below:
There, k "second-tier" nodes act as intermediaries. The target page t has only
to link to the k second-tier pages, and each of those pages links to m/k of the
m supporting pages.
Each of the supporting pages links only to t (although most of these links are
not shown).
Suppose the taxation parameter is β = 0.85, and x is the amount of PageRank
supplied from outside to the target page. Let n be the total number of pages
in the Web. Finally, let y be the PageRank of target page t.
If we compute the formula for y in terms of k, m, and n, we get a formula with the form
y = ax + bm/n + ck/n
Note: To arrive at this form, it is necessary at the last step
to drop a low-order term that is a fraction of 1/n.
Determine coefficients a, b, and c, remembering that β is fixed at 0.85.
Then, identify the value, correct to two decimal places, for one of these coefficients.