The continuous timing method is used to direct time study a manual task cycle

consisting of four elements: a$,$ b$,$ c$,$ and d$.$ Two parts are produced each cycle.

Element d is an irregular element performed once every six cycles. All elements were

performance rated at $90\%.$ The PFD allowance is $11\%.$ Determine $($a$)$ the normalized

time for the cycle and $($b$)$ the standard time per part. $($c$)$ If the worker completes $844$

parts in an $8-$hour shift during which she works $7$ hours and $10$ min, what is the

worker$$s efficiency?

Element a b c d

Observed time $($min$)0\mathrm{.}350\mathrm{.}600\mathrm{.}861\mathrm{.}46$