$3\mathrm{.}1$ An assembly line whose activities are shown in the table below has a demand of $45$ units per day. The assembly line is in operation $9$ hours a day.

$\backslash$table$[[$Activity$,$Immediate predecessor$/$s$,$Performance Time $($minutes$)],[$A$,$None,$5],[$B$,$A$,3],[$C$,$A$,4],[$D$,$A$,5]]$

EPTEEt

$\backslash$table$[[$E$,$B$,$C$,3],[$F$,$B$,6],[6,$D$.$E$.$F$,3],[$H$,$F$,$G$,7],[$I$,$H$,4],[$J$,$H$,$ I,$5]]$

$3\mathrm{.}1\mathrm{.}1$ Draw the precedence diagram.

$(4)$

$3\mathrm{.}1\mathrm{.}2$ Calculate the cycle time.

$(2)$

$3\mathrm{.}1\mathrm{.}3$ Determine the minimum number of workstations required.

$3\mathrm{.}1\mathrm{.}4$ Assign tasks to workstations. Show the cumulative station times as well as the unassigned station times.

$(10)$

$3\mathrm{.}1\mathrm{.}5$ Calculate the overall efficiency of the assembly line with minimum number of workstations.

$(2)$