Calculating a Value from Weighted Average

[oakwood_001]

Hi All,

My inequality algebra isn't what it used to be.

I'm not even sure if this is possible but can I back calculate the time values from the weighted average shown below:

1.38 = ((794*1.3)+(221*1.67))/794+221

weighted avg = (volume * time)+(volume * time) etc. etc. / total volume

In spreadsheet terms I have the volumes and times in a column and the weighted average elsewhere.

Thanks,

Pat

 

[oakwood_001]

Thinking about it more - is this impossible as there are 2 (or more) variables which could be theoretically be anything providing the answer came to 1.38.

Does anyone concur?

In which case I'm screwed.