What you have to understand about Google is it was originally conceived to rank webpages based on links to the webpage. More links flowing to a page, higher the page should be ranked.
In reality it’s not that simple, all webpages are not equal when it comes to passing on PageRank/PR, but the basic premise holds, more links = better rankings.
See image for a better idea how PR is distributed via links, PR flows though links and ‘accumulates’ on pages where more PageRank flows through.
Pages B and C gain more PR, but note Page C only has the one link from Page B, that’s because Page B only links to Page C passing on approximately 85% of it’s ‘accumulated’ PR.
PageRank is one of over 200 Google ranking factors, high PR (lots of backlinks) is only one factor in high Google rankings.
Continue Reading Google PageRank and Page Rank