precedence network is shown in the figure below; task times in minutes are given in parentheses. There are $480$ minutes of assembly time per shift and the company operates one shift each day. The required output rate is forecasted to be $60$ units per shift.

a$)$ Balance the assembly using the longest processing time rule. State the tasks associated with each workstation, total time, idle time $($Hint: first calculate the cycle time using formula in slide $29$ of Lecture $8c$ then group them referring to sides $30$ to $32,$ summarize them in a table similigr. to Problem $3)$

b$)$ What is the assembly line efficiency $($Hint: formulo on silde $26$ of Lecture $8$c$)$