Domain or Sub-Domain PR

So here's my question:

If a domain has a PR of 7 and it has a subdomain with PR of 4. If I get a backlink from the subdomain, does it take the juice from the domain or the subdomain?

Thanks.

It's quite hard to understand this kind of stuff sometimes, the answer is nope.

Your domain takes juice from the subdomain, which simultaneously takes juice from the main domain (ONLY IF THE MAIN DOMAIN HAS A LINK POINTING TO THE SUBDOMAIN).

So, your domain does benefit from the main domain's link juice. However it benefits indirectly through the subdomain.

let me know if you didn't understand.