Table 922
the Production of a Particular Product Consists of Seven

Table 9.22
The production of a particular product consists of seven work elements. The desired output rate is 60 units per hour. The work element and their precedence relationships are given.
$$\begin{array} { | c | c | c | } \hline \begin{array} { c } \text { Work } \\\text { Element }\end{array} & \text { Time (sec) } & \begin{array} { c } \text { Immediate } \\\text { Predecessor(s) }\end{array} \\\hline 1 & 30 & - - \\2 & 15 & 1 \\3 & 20 & 2 \\4 & 15 & 3 \\5 & 30 & 3 \\6 & 25 & 4 \\7 & 30 & 5,6 \\\hline\end{array}$$
-Use the information in Table 9.22.What is the efficiency of the line created using the longest work-element time rule?

A) less than or equal to 70%
B) more than 70% but less than or equal to 75%
C) more than 75% but less than or equal to 80%
D) more than 80%