Refer to the following mentioned data. In millions) 2017 2016 2015 Net sales $34,103 $30,733 $26,412 Cost of products sold 14,147 13,634 13,808 Gross margin $19,956 $17,699 $12,684 ok Required: a. Calculate the gross profit ratio for each of the past three years. (Round your answers to 2 decimal places.) ht 2017 2016 2015 58.52% 55,64% 47.72% onces b. Assume that Campbell's net sales for the first four months of 2018 totaled $12.7 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 milion million