I have a s/s that has the months of the year across the top and below 3
categories for each month and I want a weighted avg for each product. eg:
A B C D E F G H I
January February March etc. to Dec
Days Oil Gas Days OIl Gas Days Oil Gas
6 12 200 4 5 180 7 8 300
formula: =(a1*b1+D1*E1+G1*h1)/(a1+d1+g1)

Is there a way to simplify this? Thank in advance for any help.
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ferne