The computer solution is shown below.

Optimal Objective Value $=17040\mathrm{.}00000$

$\backslash$table$[[$Variable$,$Value,Reduced Cost$],[$E$,180\mathrm{.}00000,0\mathrm{.}00000],[$S$,60\mathrm{.}00000,0\mathrm{.}00000],[$D$,0\mathrm{.}00000,24\mathrm{.}00000],[,,],[$Constraint$,$Slack $\frac{?}{?}$ Surolus,Dual$],[1,0\mathrm{.}00000,31\mathrm{.}00000],[2,0\mathrm{.}00000,32\mathrm{.}00000],[3,440\mathrm{.}00000,0\mathrm{.}00000]]$

$\backslash$table$[[$Variable$,$Objective,Allowable,Allowable$],[$Coefficient$,$Increase,Decrease,$],[$E$,63\mathrm{.}00000,12\mathrm{.}00000,15\mathrm{.}50000],[$S$,95\mathrm{.}00000,31\mathrm{.}00000,8\mathrm{.}00000],[$D$,135\mathrm{.}00000,24\mathrm{.}00000,$Infinite$],[,,,],[$Constraint$,$RHS$,$Zlloweble,Allowable$],[1,$Value,Increase,Decrease$],[2,240\mathrm{.}00000,60\mathrm{.}00000,90\mathrm{.}00000],[3,300\mathrm{.}00000,110\mathrm{.}00000,60\mathrm{.}00000],[,2600\mathrm{.}00000,$Infinite,$440\mathrm{.}00000]]$

$($a$)$ What is the optimal solution, and what is the value of the objective function?