Refer to the following mentioned data.

	(In millions)
	2017			2016			2015
Net sales	$	34,058		$	30,174		$	26,635
Cost of products sold		14,910			13,485			13,474
Gross margin	$	19,148		$	16,689		$	13,161

Required: a. Calculate the gross profit ratio for each of the past three years. (Round your answers to 2 decimal places.)

b. Assume that Campbells net sales for the first four months of 2018 totaled $12.39 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).)