Please provide detailed explanation .

Determine how many rate of (ROR) values the following cash flow series might have using the corresponding rules of sign changes. Explain all clearly. Decide on the actual ROR roots, and indicate them on the net present profile accordingly. Year Cash Flow 0 1 $ 4,000 $1,600 $ 1,200 $ 600 2 2 3 4 $300 5 -850 6 + 1,500 + 1,000 7 8 + 500