A factory produces two types of items, Item P and Item Q. Each unit of Item P requires hours of machine time, and each unit of Item Q requires hours of machine time. The total machine time available for production is hours. The graph representing all possible combinations of units of Item P () and units of Item Q () that can be produced with the total available machine time is a line on a coordinate plane. This line passes through the points and , where is the maximum number of Item P that can be produced if no Item Q is produced, and is the maximum number of Item Q that can be produced if no Item P is produced. If , what is the value of ?
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