if a anchor in page A point to page B. so the anchor text as a keyword contribute relevancy to page A or B or both? if both, which get more relevancy about the keyword?
Not another one of these chicken and egg puzzles?! I believe it will contribute to both - page A because it is text content on that page and page B because that is the destination. As for relevancy, I think probably page B benefits more because, one assumes, the anchor will be related to page B's content although not necessarily page A's. CountryBoy puts on tin hat and waits for incoming flak from SEO experts.
A agree with CountryBoy... it somway affects both pages. It's often situation that stronger page where links pointing to quite weak (new) page is higher in serp.