undefined Example $3\mathrm{.}3($Past Exam Question$).$ An emergency room operates for $24$ hours and have the following number of tasks during the indicated time slots: $1234568$:$0012$:$0012$:$00-16$:$0016$:$00-20$:$0020$:$00-24$:$0024$:$004$:$004$:$00-8$:$001011171320$ Number of tasks $20$ There are three shifts starting at $8$:$00,16$:$00$ and $24$:$00.$ All nurses that start at these times can handle $2$ tasks per hour and work $8$ consecutive hours. However, some nurses ask to start at $12$:$00$ or $20$:$00$ and say that they can work more productively handling $3$ tasks per hour if they let them start at $12$:$00$ or $20$:$00$ and work $8$ consecutive hours. The emergency room pays equal salary to all nurses except for those working $24$:$00-08$:$00$ shift, who earn $20\%$ more. Formulate a linear programming model to minimize the total salaries paid.