b. Assume that Campbell's net sales for the first four months of 2018 totaled $12.53 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 million 715 million Gross profit $ Refer to the following mentioned data. (In millions) 2017 2016 2015 $30,527 13,923 $26,589 13,691 Net sales $34,437 14,783 Cost of products sold Gross margin $16,604 $19,654 $12,898 Required: a. Calculate the gross profit ratio for each of the past three years. (Round your answers to 2 decimal places.) 2017 57.07% 54.39% 2016 48.51 % 2015