Is this a subject to fit?

[Nelson Strimple]

I found a duplex on Zillow and the prior purchase price was 96k assuming they had a 80% mortgage they should owe about 71k on the property which is close to the asking price of 74k. The listing claims rental income of 1250 a month. Base on these and the current mortgage it should cash flow about 100 per door. My question is: is this a good opportunity to approach the seller about subject to? And if so, what are my next steps? Thanks in advance, Nelson