is this a good deal?

[David Sanford]

I am being offered 3 houses as a package deal for $210k. The value is $250k. It will be seller financing for 12 months and then a balloon payment will be due at which point I will pull a mortgage on them. However a bank will only give me 75% LTV which is about $190k. sooo I'll have to make up the difference of about $20k which I am fine with. my question is, is this really a deal worth pursuing? 3 year payback period and a 10% cap rate.