My time is around 20 days.
Sometimes I cannot get the real reason why the post might have been deleted, when it is accurate and on topic. However I respect the decision that admins take...
There are many reasons why your post can be deleted. It can be an off topic post or a non sensible post. When a lot of people will report your post, then it will be deleted by the mods.
If you still think your post was on topic but still deleted, you can take up the matter with admins or write more details about it.