Table 920
the Following Information Is Known About an Assembly Line

Table 9.20
The following information is known about an assembly line.
The desired output rate is 80 units per hour.
$$\begin{array} { | c | c | c | } \hline \begin{array} { c } \text { Work } \\\text { Element }\end{array} & \text { Time (sec) } & \begin{array} { c } \text { Immediate } \\\text { Predecessor } ( \mathrm { s } ) \end{array} \\\hline 1 & 1 & - - \\2 & 15 & 1 \\3 & 20 & 1 \\4 & 30 & 2 \\5 & 20 & 2,3 \\6 & 10 & 5 \\7 & 20 & 4 \\8 & 4 & 6,7 \\\hline\end{array}$$
-Use the information in Table 9.20.What is the maximum idle time at any station,given the solution found by the longest work-element time method?

A) less than or equal to 20 seconds
B) greater than 20 seconds but less than or equal to 30 seconds
C) greater than 30 seconds but less than or equal to 40 seconds
D) greater than 40 seconds