Almost anything. Our greatest experience is in economics, mathematics, statistics, analysis and marketing subjects, but we also help in other areas upon request.
Yes, it is completely flexible. Google Meet, Zoom or another platform - as convenient for you.
It is usually lasts 60 or 90 minutes long, but if the course material is too much or the Closed-door written paper/Exam is approaching, it can be longer.
It depends on how much time you have and where you are in the material now. For some, 2-3 times are enough.