Cash-on-Cash for this deal

[Jimmy NA]

How do I calculate "cash-on-cash"?

50,000 purchase price
5,000 seller concession
1,150 gross rents
575 expenses (50% gross)
6,900 NOI (yr)
690 Vacancy/Rent Loss (yr)
6,210 Adjust Rent (yr)
10,000 dwnpayment (20%)
40,000 loan
7.5 rate (%)
360 term
No points
2,000 legal/filing fees/misc. fees

The second part of the loan is an additional 30k which I get disbursed as I move along with the rehab. So, how do I calulate "cash-on-cash" with these number before I use the construction money and after?