A process requires $6$ tasks, A$,$ B$,$ C$,$ D$,$ E and F$,$ that must be performed in that order. Currently there are $3$ employees that are equally skilled at each task. Employee $1$ is assigned tasks A and B$,$ employee $2$ is assigned tasks C and D and employee $3$ is assigned tasks E and F$.$ The task times $($all in seconds$)$ are given in the process diagram below. For example, task A requires $90$ seconds.

b$.$ Suppose the system started without any work in process inventory $($i$.$e$.,$ an empty system$).$ How long would this process take to produce $55$ units $($in seconds$)?(5$ marks$)$

c$.$ Suppose now the $3$ employees can be assigned to any task, but employees must be assigned to consecutive tasks $($e$.$g$.,$ an employee cannot be assigned tasks B and D$).$ What would be the processes$$ maximum capacity $($units per hour$)?$