margin account interest basic questions

lets pretend i have 30k cash and 90k BP

1. i'm day trading, and i end up buying a 50k position and i hold overnight. i only pay interest in 20k? yes/no
2. i'm day trading going in/out/in/out multiple times in 1 day. i end up holding a position overnight worth only 20k. do i pay interest? yes/no
3. i have a margin 90k position into close, but i sell it before AH market close at ~7pm EST. do i have to pay interest on it? yes/no
4. i sold a 20k position today (so it hasn't settled), but i use that to buy a new 20k position that i decide to hold overnight. do i have to pay interest on it even though it hasn't settled? yes/no

margin account interest basic questions