Answer:
gross profit ratio = (total revenue - cost of goods sold) / total revenue
I looked for the missing information:
year total sales cost of goods sold
2012 $7,175 $4,365
2013 $8,052 $5,140
2014 $8,268 $5,370
a)
gross profit ratio:
2012 = ($7,175 - $4,365) / $7,175 = 39.16%
2013 = ($8,052 - $5,140) / $8,052 = 36.16%
2014 = ($8,268 - $5,370) / $8,268 = 35.05%
b)
since the gross profit margin ratio is decreasing every year, we can assume that it will keep decreasing in 2015. Using linear regression, the slope is -0.02055. So the estimated gross profit margin ratio for 2015 = 34.33%
estimated cogs (first four months of 2015) = $527 billion x (1 - 34.33%) = $346.08 billion
estimated gross profit (first four months of 2015) = $527 billion x 34.33% = $180.92 billion