Calculate the pool supply based on Chlorine kit usage.

The water park uses balanced chlorine kits to maintain the pools and slides at a cost of $250 per kit and the number needed is based on anticipated usage. The owner expects to use 10 in May, 20 in June, 40 in July, 40 in August and 20 in September but always wants to have 10% of next month's requirements on hand "just in case". There are 10 kits currently in inventory and he would like to have at least 5 kits at the end of the year.