Pr(spin|med) = 0.56 = Pr(spin&med)/Pr(spin) --> Pr(spin) = Pr(spin&med)/0.56 ... 1
Pr(med|spin) = 0.70 = Pr(spin&med)/Pr(med) --> Pr(med) = Pr(spin&med)/0.70 ... 2
Pr(med|med) = 0.30 = Pr(med&med)/Pr(med) --> Pr(med) = Pr(med&med)/0.30 ... 3
Pr(spin|spin) = 0.10 = Pr(spin&spin)/Pr(spin) --> Pr(spin) = Pr(spin&spin)/0.10 ... 4
Letting 1 = 4
Pr(spin&med)/0.56 = Pr(spin&spin)/0.10 --> Pr(spin&med) = [0.56*Pr(spin&spin)]/0.10 ... 5
Letting 2 = 3
Pr(spin&med)/0.70 = Pr(med&med)/0.30 --> Pr(spin&med) = [0.70*Pr(med&med)]/0.30 ... 6
Letting 5 = 6
[0.56*Pr(spin&spin)]/0.10 = [0.70*Pr(med&med)]/0.30
[Pr(spin)^2] = (35/84)[Pr(med)^2]
Pr(spin) = [(35/84)^0.5]Pr(med)
Pr(fast|[spin/med]) = 0.50 = Pr(fast&[spin/med])/Pr(fast)
= Pr{(fast)|[Pr(spin) + Pr(med) - Pr(spin&med)]}/Pr(fast)
= Pr{(fast)|[(35/84)^0.5Pr(med) + Pr(med) - 0.70Pr(med)]}/Pr(fast)
= Pr{(fast)|[0.9455Pr(med)]}/Pr(fast)