$2\mathrm{.}8.$ What follows is a raw continuous$-$timing two$-$element time study of a punch press op$-$

eration where the observations are minutes.

$($a$)$ What is the average time for each element? The ratings were $+8\%$ and $-9\%.$ What

is the normal time? A man and machine allowance of $20\%$ is used in this plant.