Complicated Average

[Zimbo760]

I need to take a cell value and average it out over a number of other cells.
So lets say I pay out $2000 (A1) in loans (they are all $100 increments but total $2000 and am due $2800 back, and on average it takes 8 months to get paid back. I need to divide the income over 16 months to make the financials work.
please help.

thanks,