total bill before any discounts $13.
she is a student, so she gets 20% off.
she brought an item of clothing, so she gets 5% off.
so she's really getting 20% + 5% off, namely 25% off her bill.

Independent variable (im pretty sure sorry if im wrong)
17+3=20
740/20=37 Classes
37 classes x 3 faculty members=111
I don’t know the answer yet, I’ll reply to my comment with it, but merry Christmas to you too!!