$2\mathrm{.}8$ A worker is responsible for loading and unloading a production machine. The load$/$unload elements in the repetitive work cycle have a normal time of only $24sec,$ and the machine cycle time is $2\mathrm{.}83$min. One part is produced each cycle. Every sixth cycle, the operator must replace the tote pans of parts, which takes $2\mathrm{.}40$min $($normal time$).$ For setting the standard time, the PFD allowance factor is $15\%$ and the machine allowance factor is $15\%.$ Determine the standard time under the following alternative assumptions: $($a$)$ the irregular element is performed as an extemal element and $($b$)$ the irrefjular element is performed as an internal