and it have seo benefit because of the dedicated ips?Each IP is unique (but what it's used for may not be unique). Dedicated IPs (ex: not used for anything else) are normally required for SSL enabled sites. You can easily run 10 domains off 1 IP but if they require SSL on each then you will need atleast 10 IPs. 20 if you want to make your life easy.
A domain is a .com, .net, .org etc. It's pretty much a nickname for an IP so you only need to remember google.com rather than 173.194.75.101
and it have seo benefit because of the dedicated ips?
A dedicated IP doesnt give a positive SEO benefit, merely a neutral benefit. Having your site on the same IP as some lower quality sites (ex: porn, gambling, illegal) has some chance to decrease SEO so getting it off of the IP will bring you back to a neutral standing. It does not give you a positive benefit like correct use of H1 headers, meta tags etc.
on same hosting how many sites we can keep ?
on same hosting how many sites we can keep ?