Period

$1$

$2$

$3$

$4$

$5$

$6$

$7$

$8$

$9$

$10$

Gross requirements

$25$

$20$

$50$

$0$

$10$

$50$

$30$

$0$

$30$

$55$

$$On$-$hand at beginning of period

$25$

$25$

$0$

$60$

$10$

$10$

$0$

$60$

$30$

$30$

$0$

$$On$-$hand at end of period

$0$

$60$

$10$

$10$

$0$

$60$

$30$

$30$

$0$

$0$

Net requirements

$20$

$0$

$0$

$0$

$50$

$0$

$0$

$0$

$55$

Order receipt

$80$

$110$

$55$

Order release

$80$

$110$

$55$

The cost of this ordering system is $$$$500.$