Shoe Shine is a local retail shoe shop located on the north side of Centerville. Yearly demand for a popular sandal is 500 pairs, and John Dirk, the manager of Shoe Shine, has been in the habit of ordering 100 pairs at a time. John estimates that the ordering cost is $10 per order. The cost of the sandal is 250INR per pair. For John's ordering policy to be correct, what would the carrying cost as a percentage of the unit cost have to be? If the carrying cost were 10% of the cost, what would the optimal order quantity be?