Percentage Formula Problem

[Snit]

I've got five cells T16, T17, T18, T19, T20.
I need to Average T16, T17, T18, in cell T20 which is formatted for
Percentage.
Cell T19 is an "NA" cell which is not counted in the percentage but
does have a value.

I have the following formula: =SUM(T16/(T16+T17+T18))

Now if entries in T16 through T18 are zeros, I get the error "DIV/0!"
in cell T20 which I need to show 100.00%.

I'd really appreciate any help on this matter.

 

[BoniM]

I'm a little confused about where average comes into this, but if your
formula (T16 as a percentage of the total of T16:T18) gives you the answer
you need except for when you have zeros and in that case you want to see 100%
- try this:
=IF(SUM(T16:T18)=0,1,T16/(SUM(T16:T18)))

 

[Snit]

I was little confused also.

What is happening is that cells T16, T17 & T18 are three different
ratings for a set number of Systems.

i.e. 7 Systems that have the ratings cell T16"Good", cell
T17"Deficiency", cell T18"Extereme Deficiency" with cell T19 as "Non
Applicable" or "NA".

So what happens in cell T20 is that I need the following:

Percent of System in Good Repair Number of "Good" (T16) divided by
(Total Areas (T16, T17, T18, -"NA"s(T19)).

But if I had all NAs, T20 would end up as described before i.e. error
DIV/0! where I needed "100.00%" overall.

Anyway, your formula works great! I appreciate your help and hope this
reply answers your confusion.

 

[BoniM]

Thanks - nice to know we workrd thru the confusion -