luxottica group, the italian company that sells ray ban and oakley sunglasses, reported net sales of 7.1 billion in 2012 and 6.2 billion in 2011. gross profit increased from 4.1 billion in 2011 to 4.7 billion in 2012. was the increase in gross profit caused by (a) an increase in gross profit per sale, (b) an increase in sales volume, or (c) a combination of (a) and (b)?

M6-17
		Determining the Cause of Increasing Gross Profit
	Show your calculations and explain your conclusion