The purchasing agent of the company that sells the valves has found that the annual demand for them is $4,000$ units. The cost of one valve is $90\mathrm{.}00$ UAH, and the current storage costs are estimated at $10\%$ of the cost of each valve. The agent studied the costs included in the order of the valves, and concluded that the average cost of the order is $25\mathrm{.}00$ UAH in order. Moreover, it takes about $5$ days for the order to arrive from the supplier.

TASKS:

$1.$ Determine the size of the economic order and calculate the number of orders per year.

$2.$ Calculate the order interval, provided that there will be $200$ working days per year, and determine the re$-$ordering point.

$3.$ Develop a timetable for the delivery of goods from the supplier and approve it documented by an appropriate regulatory act.