Weighted average of %

[drluke]

I need to do a allocation of time spent with customers using weighted averages

I have 10 customers with a % of total of all time spent for each (I don't know the total of all time).

I spend 50% of my time with Customer A004. I need to allocate the remaining 50% of my time to the remaining customers using a weighted average of the % of total time spent, as shown in the table below. Is there a formula I can use to perform this calculation.

CUSTOMER	% Time
A001	27%
A002	15%
A003	3%
A004	8%
A005	1%
A006	4%
A007	2%
A008	18%
A009	12%
A010	10%
TOTAL TIME	100

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[sgroath]

If A001 is cell A2, then C2 should be:
=B2*(1-0.5)/(1-SUMIF(A$2:A$11,"A004",B$2:B$11))

Copy that formula down through C11 and delete it fir cell C5 and you will have your percentages to allocate.