Table 919
the Illinois Appliance Company Is Installing a Line to to Produce

Table 9.19
The Illinois Appliance Company is installing a line to produce a vacuum cleaner, and you, as the operations manager, are responsible for designing the line. The line has to produce 30 units per hour. The work elements to be performed are as follows, with the time needed and immediate predecessor(s) also shown.
$$\begin{array} { | c | c | c | } \begin{array} { c } \text { Work } \\\text { Element }\end{array} & \text { Time (sec) } & \begin{array} { c } \text { Immediate } \\\text { Predecessor(s) }\end{array} \\\hline \mathrm { A } & 55 & - - \\\text { B } & 45 & \mathrm {~A} \\\mathrm { C } & 25 & \mathrm {~B} \\\mathrm { D } & 20 & \mathrm {~B} \\\mathrm { E } & 40 & \mathrm {~B} \\\mathrm {~F} & 50 & \mathrm { D } \\\mathrm { G } & 70 & \mathrm { D } \\\mathrm { H } & 45 & \mathrm {~F} , \mathrm { G } \\\mathrm { I } & 20 & \mathrm { E } \\\mathrm { J } & 80 & \mathrm { H } , \mathrm { I } \\\hline\end{array}$$
-The production of a product consists of seven work elements.The desired output rate is 2 units per minute.The work elements and their precedence relationships follow.
$$\begin{array} { | c | c | c | } \hline \begin{array} { c } \text { Work } \\\text { Element }\end{array} & \text { Time (sec) } & \begin{array} { c } \text { Immediate } \\\text { Predecessor(s) }\end{array} \\\hline 1 & 15 & - - \\2 & 16 & 1 \\3 & 12 & 2 \\4 & 14 & 3 \\5 & 18 & 2,4 \\6 & 12 & 5 \\7 & 20 & 4 \\\hline\end{array}$$
Using the longest work-element time method,how many stations are required?

A) 2 stations
B) 3 stations
C) 4 stations
D) 5 stations