More general system

Each entering flow unit first splits into two parts $-$ the first part goes through stages A and B$,$

and the second part is processed concurrently through stage C$.$ E$.$g$.,$ in a doctor's office, one

part is the patient, and the other part is the paperwork $($e$.$g$.,$ billing$)$ for this patient. After the

processing for both parts is completed, the two parts of the flow unit are re$-$assembled, and

the unit leaves the system.

What is system capacity if processing times at stages $A,B,C$ are respectively $T_A,T_B,$ and

$T_C$ minutes$/$flow unit $($per server, at stage C $)?$