A particular manufacturer of charcoal briquettes is contracted to create a product that contains no more than 0.1 mass fraction moisture and no more than 0.1 mass fraction ash. For one production batch, the basic material available has 12.4 mass percent moisture, 16.6 mass percent volatile material, 57.5 mass percent carbon, and 13.5 mass percent ash. To meet the specifications of its contract, the manufacturer plans to mix this material with a certain amount of petroleum coke that has a composition of 8.2% volatile material, 3.1% moisture, and 88.7% carbon by mass. How much petroleum coke must be added per 100 lb of basic material? Before solving, draw a flowchart and conduct a degree of freedom analysis.