Need explain answer

01 : ABC Company have the following information for 2006, 2007 2006 2007 Cash 200000 300000 Inventory 100000 120000 A/R 25000 30000 Allowance of doubt account 2500 Equipment's 150000 170000 Accumulated depreciation 15000 20000 Net sales 1000000 Net operating income 50000 Cost of goods sold 650000 Operating expenses 90000 Tax income 20% Required: Compute the ROI for 2007