probabilities of visits:
Friday: P(A)=3/4,P(B)=1/4
Saturday: P(B)=3/4,P(A)=1/4⋅3/4=3/16,P(C)=1/4⋅1/4=1/16
Sunday:
P(A1)=3/4⋅3/4=9/16,P(A2)=1/16⋅3/4=3/64
P(B1)=3/16,P(B2)=1/16⋅1/4=1/64
P(C)=3/4⋅1/4=3/16
Monday:
P(A1)=3/16⋅3/4=9/64,P(A2)=3/16⋅3/4=9/64
P(A3)=1/64⋅3/4=3/256
P(B1)=9/64,P(B2)=3/16⋅1/4=3/64,P(B3)=3/64
P(C1)=3/16⋅1/4=3/64,P(C2)=1/64⋅1/4=1/256
Tuesday:
P(A)=9/64⋅3/4+3/64⋅3/4+3/64⋅3/4+3/64⋅3/4+1/256⋅3/4=219/1024
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