A certain item costs Rs$.250/-$ per tonne. The monthly requirement is $5$ tonnes and ordering costs work out to Rs$.120$ per order. With an interest carrying rate of $10\%$ of the value of the stock per year, calculate $(1)$ the EOQ; $($ii$)$ the reorder point, assuming the lead time of three months; $($iii$)$ the intervals after which the orders should be placed.