Is this a deal?

[Jim Viens]

Looking at an 75 year old 2600 sq ft 3/1 raised ranch on 1.8 acre lot. structure is good but the floor plan needs a little adjustment (including adding at least a half-bath). Estimating total rehab costs at around $55k with an ARV of about $110,000 (based on sold comps in the area). I may have a contractor friend walk the property with me to verify the rehab cost. It's a foreclosure listed for $39,900 but I'm thinking of putting in an offer of $20,000. Would this be a decent flip deal at that offer?