Do you think that 250 pages (1 page = 500 words) of quality content on my website would be enough for me to generate an income of 50 dollars per day with Adsense?
It depends a lot about how you titled your webpages as to whether or not you will receive any traffic. A lot of people make the mistake of using very generic terms in their titles and wonder why their sites never show up in searches even though they have hundreds of pages.
It is quality not quantity. You can have 100,000's of pages and could be worse off than a 1 page site.