This is a question that many bloggers face, if you are an established blogger you know all the thing but if you are a new blogger you should be thinking about it. If you see Problogger and DailyBlogTips, both blogs publish a post a day, because they have large readership and they are not trying to increase their readership but they are trying to secure their readership.
But if you see many new bloggers try to post more and more post in a day. Because they want to have all the content that other bloggers have and they want more and more visit from search engines.
I was talking about how many posts you can compose in a day? If I talk about how many I can compose I will say 25 posts per day. But it depend on post quality, post topic, post length. If you work hard on a post and the post is long and you have to research and think before writing then one post will be composed in a day. One more reason is also very important for how many posts you can compose in a day. Many established bloggers do not spent more than two hours in a day on a single blog.
If you are posting just a news then news publishing does not take so much time to compose and publish. If you are going to post a list with description you will create a list first, after you will write a description for that list and it will take time.
This is the reason sometimes I post only a post and sometimes three to five posts.