$7$ Each hour from $10$ A$.$M$.$ to $7$ P$.$M$.,$ Bank One receives

checks and must process them. Its goal is to process all the

checks the same day they are received. The bank has $13$

check$-$processing machines, each of which can process up

to $500$ checks per hour. It takes one worker to operate each

machine. Bank One hires both full$-$time and part$-$time

workers. Full$-$time workers work $10$ A$.$M$.6$ P$.$M$.,11$ A$.$M$.$

$7$ P$.$M$.,$ or Noon$8$ P$.$M$.$ and are paid $$160$ per day. Part$-$time

workers work either $2$ P$.$M$.7$ P$.$M$.$ or $3$ P$.$M$.8$ P$.$M$.$ and are

paid $$75$ per day. The number of checks received each hour

is given in Table $6.$ In the interest of maintaining continuity,

Bank One believes it must have at least three full$-$time

workers under contract. Develop a cost$-$minimizing work

schedule that processes all checks by $8$ P$.$M$.$