This will give you an idea of how many inbound links and what Page Rank those inbound links need to be, for your website to obtain the desired PageRank for your pages.
These pagerank algorithm equation is the relationship between two pages A and B, with the below example page A receiving an inbound link from page B.
PR-A = (0.15) + (0.85 x
PR-B / TOL-B)
PR-A is the PageRank of Page A,
PR-B is the PageRank of Page B, and TOL-B is the Total Outbound Links of Page B.
Example: If you get an inbound link from a page that has a PageRank of 6 and on that page there is a total of 6 outbound links (counting the one to your page), a
PR of 1 will be added to your page: 0.15 + (0.85 x 6/6) = 1. If that one inbound link adds a PageRank of 1 to your page, and you wanted a
PR of 5 it would take 5 similar inbound links.
By similar I mean pages that have a
PR/TOL ratio of 1. That could be a PageRank of 5 with 5 outbound links, or a PageRank of 7 with 7 out bound links and so on. A
PR/TOL ratio of 1 will add to your page a PageRank of 1. Using the
PR/TOL ratio simplifies the RageRank algorithm equation and makes it easier for you to evaulate what
PR a inbound link will add to your page.
When you are looking for inbound links just divide the PageRank of the page by its outbound links and this will give you a general idea of the PageRank a inbound link from that page would give you.