XYZ Ltd$.$ Buys $75000$ glass bottles per year. Price of each bottle is R$\mathrm{.}0\mathrm{.}90.$ Cost of purchase is Rs$\mathrm{.}100$ per order. Cost of holding one bottle per year is Rs$\mathrm{.}0\mathrm{.}20.$ Bank interest is $15\%$ including a charge for taxes and insurance on the price.

a$)$ Find out EOQ quantity.

b$)$ What inventory costs are incurred with this ordering quantity?