Balance the Assembly Line Using the Information Below,and the Longest

Balance the assembly line using the information below,and the longest work-element time rule.The desired output is 360 units per day.Available production time per day is 480 minutes.What is the efficiency for the balanced assembly line?
$$\begin{array} { | c | c | c | } \hline \begin{array} { c } \text { Work } \\\text { Element }\end{array} & \begin{array} { c } \text { Time } \\( \mathrm { sec } )\end{array} & \begin{array} { c } \text { Immediate } \\\text { Predecessor } ( \mathrm { s } )\end{array} \\\mathrm { A } & 30 & - \cdots \\\mathrm { B } & 20 & \mathrm {~A} \\\mathrm { C } & 50 & \mathrm {~A} \\\mathrm { D } & 45 & \mathrm {~B} \\\mathrm { E } & 30 & \mathrm {~B} \\\mathrm {~F} & 55 & \mathrm { C } , \mathrm { D } \\\mathrm { G } & 35 & \mathrm { D } , \mathrm { E } \\\mathrm { H } & 40 & \\\hline\end{array}$$