4 For the Dorian Auto problem (Example 2 in Chapter 3), a Find the range of values on the cost of a comedy ad for which the current basis remains optimal.

b Find the range of values on the cost of a football ad for which the current basis remains optimal.

c Find the range of values for required HIW exposures for which the current basis remains optimal. Determine the new optimal solution if 28 

million HIW exposures are required.

d Find the range of values for required HIM exposures for which the current basis remains optimal. Determine the new optimal solution if 24 

million HIM exposures are required.

e Find the shadow price of each constraint.

f If 26 million HIW exposures are required, determine the new optimal z-value.