A business buys chairs, puts them through a finishing process and the sells them. At the beginning of june the store manager realizes that there are only 35 chairs in inventory and wants to know how many he will need to order in each of the next three months. He ascertains that planned sales for the next three months and planned closing inventories of chairs in units are as follows: June July August Planned sales 120 150 130 Closing inventories 60 70 50 How many chairs must he order each month?