Does Google consider no follow links along with do follow links while determining PR of a particular page.
To determine PR Google won't consider no follow backlinks. PR determination depends on several factors. Try to read Google Corporate overview.
No follow links don't pass on any pr but they are still valuable links to have. Don't forget about the other search engines and traffic from the link itself.
Nofollow links don't officially count towards PageRank, but as jasonb says they are important. Nofollow links contribute to a natural link profile - a site with only dofollow links is likely appears suspicious.
Yup... Sometimes if someone says that their domain have hundreds even thousands of backlink, maybe they include the no-follow backlink.