Let's say i have two pages on a web. One hosting non-adult where i show adsense and one showing adult content where i use adbrite or any adult company ads. Is it allowed?
2 pages on a web implies to me they are on the same domain - in this case NO it's not allowed from an AdSense point of view.
So long as AdSense is not on the adult site, I do not see a problem. Ultimately, you should read the TOS or email google.