(In millions) 2017 2016 2015 Net sales $34,822 $30,868 $26,827 Cost of products sold 14,406 13,825 13,851 $20,416 $17,043 $12,976 Gross margin Required: a. Calculate the gross profit ratio for each of the past three years. (Round your answers to 2 decimal places.) 2017 2016 2015 58.63% 55.21% 48 37% b. Assume that Campbell's net sales for the first four months of 2018 totaled $12.33 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 (i.e., 5,000,000 should be entered as 5).) Cost of goods sold Gross profit million $ 7 million