How many scanned pages fit in 200 KB?

Usually two to four, depending on how detailed the pages are. Plain black-and-white text pages compress better than colour photos or stamps.

My file is 2 MB. Can it really get under 200 KB?

If the size comes from scanned or photographed pages, often yes. If the PDF is mostly text and vector graphics, it is already compact and this tool won't shrink it much.

Compress PDF to 200 KB