Answer:
Compute the accounts receivable turnover for 2018.
4.29 times
Compute the inventory turnover for 2018
3.6 times
Compute the net margin for 2017.
24.58%
Explanation:
 Compute the accounts receivable turnover for 2018.
 accounts receivable turnover = Sales / Accounts receivable
                                                   =  $ 2,400,000 / $ 560,000
                                                   = 4.29 times
Compute the inventory turnover for 2018
 Inventory turnover = cost of Sales / inventory
                                 = $1,800,000 /  $ 500,000
                                 = 3.6 times
Compute the net margin for 2017.
net margin = Net Profit / Sales × 100
                   = (2,400,000-1,810,000) / 2,400,000  × 100
                   = 24.58%