The time t in hours, employees are on the working on assembling widgets. The employee rate of change of productivity in units per hour is described by

$\displaystyle {r}{\left({t}\right)}=\frac{{{128}{\left({t}^{{2}}+{8}{t}\right)}}}{{{t}^{{3}}+{6}{t}+{12}}},{0}\le{t}\le{8}$

$\displaystyle \lim_{{{t}\rightarrow{2}}}{r}{\left({t}\right)}=$ units per hour

If needed round to 4 decimal places