Multiplying preceding rows by certain percentages

[linusho]

I have a list of dates and revenues but want to attribute a certain percentage of revenues to other dates. For instance:

Day 1:  5

Day 2:  10

Day 3:  10

Day 4:  5

Assuming that the day of should receive 50% of revenue, the day preceding should contribute 25%, and the 2 days preceding 25% the output would be:

Day 1: 2.5

Day 2: 7.5

Day 3: 8.75

Day 4: 7.5

How would I approach this? I have hundreds of rows of dates+revenues and am actually allocating to the 12 days preceding but haven't figured out a way to approach this problem. Thanks.

Attached another sample below for further clarification.

[BrandonB]

What do you do in cases where there is not a day preceding? This would result in 25% dropping off.

[linusho]

Ideally those would be null and I could just filter those dates out later but since the date window is static in this instance I could always just remove the affected values with a sample tool--inelegant but it works.

[BrandonB · Accepted solution]

You should be able to use a multi row tool and set it up like this. Workflow is also attached. 

[linusho]

Doh! I totally forgot about the num rows option box. Thanks for the solution.