Net sales Cost of products sold Gross margin (In millions) 2017 2016 2015 $34,215 $30,704 $26,498 14,093 13,560 13,323 $20,122 $17,144 $13,175 Required: a. Calculate the gross profit ratio for each of the past three years. (Round your answers to 2 decimal places.) 2017 2016 2015 58.811% 55.84 % 49.72% b. Assume that Campbell's net sales for the first four months of 2018 totaled $12.14 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 profil million million