2017 2015 Net sales Cost of products sold Gross margin (In millions 2016 $34,864 $30,088 $26, 307 14,188 13,395 13,512 $20,676 $16,693 $12,795 Required: a. Calculate the gross profit ratio for each of the past three years. (Round your answers to 2 decimal places.) % 2017 2016 2015 % % b. Assume that Campbell's net sales for the first four months of 2018 totaled $12.71 billion. Calculate an estimated cost of goods sold and gross profit for the four months, using the gross profit ratio for 2017. (Round intermediate calculations to 2 decimal places. Enter your answers in millions rounded to nearest whole number (.e., 5,000,000 should be entered as 5).) Cost of goods sold Gross profit million million