Question 1122175
These three items are given in the 2nd sentence:
P(SC) = 0.20
P(SQ | SC) = 0.60
P(SC | SQ) = 0.30  
I am interpreting "if a customer uses the squash courts they also take supercircuit classes" as "given the customer uses the squash courts, they also take supercircuit classes"  for if I interpret this as SC & SQ, the math does not work ( 0.30 does not equal (0.60)*(0.20) ). <br>

1. P(SQ | SC) = 0.60    
2. P(SC & SQ) = P(SQ | SC) * P(SC)  =  0.60 * 0.20 = 0.12
3. P(SC) = 0.20 <br>

That you posted this question with the answers so readily available tells me you very likely need to increase your effort here.