A direct time study was taken on a manual work element

using the snapback method. The regular cycle consisted

of three elements, a$,$ b$,$ and c$.$ Element d is an irregular

element performed every five cycles. The average values

for observed times and performance ratings are given for

the work elements.

Work element a b c d

Avg. obs. time $($min$)0\mathrm{.}560\mathrm{.}250\mathrm{.}501\mathrm{.}10$

Avg. perf. rating $100\%80\%110\%100\%$

$$ Determine $($a$)$ normal time and $($b$)$ standard time for the

cycle $($Allowance factor is $15\%)$