But you need to factor in the insurance, $3600 (last figure was assumed to be your property tax.
vacancy: we assumed 100% occupancy rate
If you sell it at $310 the return on the investment would be 4.3% before all other expenses
You are doing good with that kind of ROI for the Bay Area.
Keller Wms Cupertino Realty
The formula for ROI is as follows:
gain from investment - cost of investment / cost of investment
Check out this website for a great, easy to use calculator to help you come up with your ROI:
Hope this helps!