Work methods

Problem $2\mathrm{.}3$

The normal time to perform a certain manual work cycle is $3\mathrm{.}47$min. In addition, an irregular work element whose normal time is $3\mathrm{.}70$min must be performed every $10$ cycles. One work unit is produced each cycle. The PFD allowance factor is $14\%.$ Determine $($a$)$ the standard time per piece and $($b$)$ how many work units are produced during an $8-$hour shift at $100\%$ performance, and the worker works exactly $7\mathrm{.}018hr,$ which corresponds to the $14\%$ allowance factor. $($c$)$ If the worker's pace is $120\%$ and he works $7\mathrm{.}2$ hours during the regular shift, how many units are produced?