A firm's balance sheets for year-end 2011 and 2012 contain the following data. All items are in millions of dollars. Accounts receivable Inventories Accounts payable Dec. 31, 2011 36.4 30.4 26.4 Dec. 31, 2012 32.8 25.8 12.8 a. Calculate the net working capital in 2011. (Enter your answer in millions rounded to 1 decimal place.) Net working capital million b. Calculate the net working capital in 2012. (Enter your answer in millions rounded to 1 decimal place.) Net working capital million c. What happened to investment in net working capital during 2012? (Input the amount as a positive value. Enter your answer in millions rounded to 1 decimal place.) Net working capital has (Click to select) by $ million