Final answer:
To determine the total units sold by flavor for each quarter, analyze the values in the 2009 Sales and 2010 Sales worksheets. Use the SUMIFS function in the Summary worksheet to calculate the total units sold for each flavor in each quarter.
Step-by-step explanation:
To determine the total units sold by flavor for each quarter, you need to analyze the values in the 2009 Sales and 2010 Sales worksheets. In the Summary worksheet, you can create a formula to calculate the total units sold by flavor for each quarter. For example, to calculate the total units sold for a particular flavor in the first quarter, you can use a formula like:
=SUMIFS('2009 Sales'!$D:$D,'2009 Sales'!$A:$A,'Summary'!$A2,'2009 Sales'!$B:$B,'Summary'!B$1)+SUMIFS('2010 Sales'!$D:$D,'2010 Sales'!$A:$A,'Summary'!$A2,'2010 Sales'!$B:$B,'Summary'!B$1)
Repeat this formula for each flavor and quarter to calculate the total units sold. This will give you the desired result of the total units sold by flavor for each quarter.