The Geek of the Year store stocks and sells personal computer of type IQ69 for which demand is uniform and constant. Every 3 months, when the stock level fall down to 100 units of IQ69, they place an order for 1800 units of IQ69. If the store uses 300 units of IQ69 to cover open orders every time they give/receive a new shipment, calculate the a) daily demand b) duration of phase 1 c) duration of phase 2 d) lead time duration