$.$a mail order house uses $18000$ boxes a year, carrying costs are $60$ cents per box a year, and ordering cost are $$96.$ The following price schedule applies. Determine the following $$

A$.$ The optimal ordering quantity $$

B$.$ The number of orders per year$$

Number of boxes price per box$$

$1000-1999$ $$1\mathrm{.}25$

$2000-49991\mathrm{.}20$

$5000-99991\mathrm{.}15$

$10000$ or more $1\mathrm{.}10$