Suppose that a tutor wants to teach me and I want to ask him how long the class will take but I'm not sure how

to ask it. These are my self-made examples: Suppose that per session is "1:30 minutes" (one hour and a half)

1. May I know how long your class take?

2. May I know how many minutes does your class take long?

3. May I know how long does your tutoring take long?

4. May I know how long does your private lessons take long?

5. May I know how long your individual class take long?

I'm confused. I don't know how to ask or know the timing of per class (session). What's the proper way to ask it?

Thank you