Here's a description of spreadsheet that I am making for the sales of a sto

- Column A has all the dates of the year (January 1, January 2, January 3,
etc.) for the entire year listed one after another (so a total of 365 rows,
starting in row 1).
- Column B has the day of the week (Monday, Tuesday, Wednesday, etc.)
corresponding to the date next to it in column A.
- Column C has the sales amount (example: $125.50) corresponding to the
date/day listed in the same row of columns A and B.

I have the following formula (which works great) which gives me the SUM of
all sales made ONLY on MONDAYS for the entire year to appear in a cell:
=SUMIF(B:B,"MONDAY",C:C)

My question is:
Is there a formula that would allow Excel to calculate the AVERAGE
(excluding blank cells and cells with zeros!) of all sales made ONLY on
MONDAYS for the entire
year? I have tried to modify the formula above to do that, but to no avail.
I know not what I am doing! Can anyone help?

Thanks in advance!