How to represent mathematical progressions or decays in EXCEL?

[excelos]

Hello!

I have in a cell a number which is the initial amount and in another cell a rate of decay. That rate can be a number by which you reduce the initial amount or a decay percentage by which again you reduce the initial amount.

How can I write a formula that will calculate the decay of this amount?

Thanks!

 

[shg]

[Table="width:, class:grid"][tr][td="bgcolor:#C0C0C0"][/td][td="bgcolor:#C0C0C0"]

A​

[/td][td="bgcolor:#C0C0C0"]

B​

[/td][/tr][tr][td="bgcolor:#C0C0C0"]

1​

[/td][td]

90%​

[/td][td][/td][/tr]
[tr][td="bgcolor:#C0C0C0"]

2​

[/td][td][/td][td][/td][/tr]
[tr][td="bgcolor:#C0C0C0"]

3​

[/td][td]

1​

[/td][td]A3: Input[/td][/tr]
[tr][td="bgcolor:#C0C0C0"]

4​

[/td][td="bgcolor:#E5E5E5"]

0.9​

[/td][td]A4: =$A$1*A3[/td][/tr]
[tr][td="bgcolor:#C0C0C0"]

5​

[/td][td="bgcolor:#E5E5E5"]

0.81​

[/td][td][/td][/tr]
[tr][td="bgcolor:#C0C0C0"]

6​

[/td][td="bgcolor:#E5E5E5"]

0.729​

[/td][td][/td][/tr]
[tr][td="bgcolor:#C0C0C0"]

7​

[/td][td="bgcolor:#E5E5E5"]

0.6561​

[/td][td][/td][/tr]
[tr][td="bgcolor:#C0C0C0"]

8​

[/td][td="bgcolor:#E5E5E5"]

0.59049​

[/td][td][/td][/tr]
[tr][td="bgcolor:#C0C0C0"]

9​

[/td][td="bgcolor:#E5E5E5"]

0.531441​

[/td][td][/td][/tr]
[tr][td="bgcolor:#C0C0C0"]

10​

[/td][td="bgcolor:#E5E5E5"]

0.478297​

[/td][td][/td][/tr]
[/table]

 

[excelos]

Thanks,

I have 1000 files. Each day, 250 files are processed. Out of the processed files, 20% get completed. Out of the processed files, 80% files need reprocessing and they restart from the beginning, but after second processing, they get completed.

How can I model this in excel to show the decline of files to be processed per day? In a function, that I can drag to generate the sequence?

thanks!