# Do I need to calculate the weighted average in these cases?

I'm aware of the concept of calculating a weighted average but the data I'm working with is confusing me. I couldn't find any similar examples when I did a search.

Here's an example. We have a number of leads generated for every day of the week. In this case the cost per lead generated is not fixed, nor is the revenue generated per lead. I've calculated the Profit by taking the revenue and subtracting the cost. Then I use that to calculate the average profit per lead for each day. The final column is the ratio between the cost and the revenue on each day (Cost / Revenue).

As you can see there are days were no profit is made and the Cost / Revenue ration is Div/0 (infinite).

My question is, how do I determine the average Profit Per Lead for the whole week, and the average Cost / Revenue Ratio for the whole week?

Day Leads    Cost   Revenue  Profit   Profit Per.L   Cost/Revenue Ratio
M   100      20     70       50       0.5            28.57%
T   200      10     80       70       0.35           12.5%
W   250      15     120      105      0.42           12.5%
T   75       30     100      70       0.93           30%
F   140      70     75       5        0.04           93.33%
S   160      80     0        -80      -0.5           Div/0
S   100      25     90       65       0.65           27.78%


Do I...

A:

SUM the PPL and divide it by 7?

SUM the C/R Ratio and divide by 6. Though that would not take in to account that Saturday which was very poor. Should I substitute 100% in stead of 0 and divide by 7?

or

B:

( SUM Profit ) / ( SUM number of Leads) = Average PPL for the week?

( SUM Revenue ) / ( SUM Revenue ) = Average Cost / Revenue ration for the week?

Thanks