Michael L Wrote:
Hello,
I am an Excel newbie, and for some reason my wife has prevailed on me
to help her build a spreadsheet for her middle shool grades. Here is
the problem: She wants to calculated weighted averages, which is easy
enough (in her system, homework is 25%, quizzes 35%, and 1 test at
40%). The problem is that she wants the spreadsheet to recalculate
automatically if a test is left blank. Since there is only one test,
excel will need to re-weight the averages. So far, I have been doing
it manually for the kids who miss a test, but I want to use the IF
(ISBLANK) syntax to automate everything. Can anyone help me?
Thanks,
Mike

I will ASSUME that when the test is left blank and there is a
recalculation to be done, the percentage weights will be modified as
follows:

For homeworks : 25/(25+35) = 42%

For quizzes : 35/(25+35) = 58%

Therefore, your formula is

=IF(C2=\"\",0.42*A2+0.58*B2,0.25*A2+0.35*B2+0.40*C 2)

where

A2 = homework grades
B2 = quizzes grades
C2 = test grade

Hope is this what you are looking for.

Regards.


--
BenjieLop


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