the total amount of students in the diagram is 69, so that'd be our sample space.
P(Rhythm | Smooth)
well, from the diagram the ones who did both is 9 + 6, so our favorable outcomes is 9 + 6 = 15.

P(Rhythm | Standard)
the overlapping on both those is 6 + 10 = 16

P(Standard | Rhythm)
pretty much the same probability as before, just worded differently.
P(Rhythm | Smooth OR Standard)
well, the ones overlapping Rhythm with Smooth and Standard are 9 + 6 + 10 = 25, so 25 out of 69.
