A manager wants to assign tasks to workstations to achieve an hourly output rate of $33$ units. Assume that the shop works $60$ minutes per hour $($i$.$e$.$ no breaks$).$

a$)$ Assign the tasks shown in the following precedence network $($ times are on the nodes and are in minutes$)$ to workstations using the following heuristic rules:

i$)$ Assign the task with the most followers.

ii$)$ Tiebreaker: assign the task with the longest time.

b$)$ What is the efficiency?