A restaurant in the shopping mall is tasked with developing a work schedule for both

full$-$time and part$-$time waiters to ensure there is enough staff to serve the customers.

You have recommended the use of a model to determine the most efficient waiter

schedule. Important information related to this schedule is given below:

$$ Business starts from $11$AM to $8$PM$.$

$$ Each full$-$time waiter starts on the hour and works a $4-$hour shift, followed by $1$

hour for break and then another $3-$hour shift.

$$ Number of full$-$time waiters is between $5$ and $10.$

$$ There should always be at least two full$-$time waiters on duty at all times.

$$ RM$25$ per hour for the full$-$time waiter, and RM$10$ per hour for part$-$time waiter.

$$ Part$-$time waiter can work either $3-$hour or $4-$hour shift.

$$ Maximum number of part$-$time waiters is $15.$

Formulate and determine an optimal schedule for the staff, taking into consideration

the minimum number of waiters required in each hour. Present your optimal schedule

in a diagram.