Slab on grade foundation problems

[Samantha Klein]

Okay guys, this duplex has some what looks like serious foundation issues going on, this is a duplex built in 1895 and is a slab on grade foundation. Gutters were only recently added and my thought is poor drainage was the problem. There are other cracks than these, the ceiling in one closet is pulling away from the wall about 1/2". What does this typically cost to repair and what would the repair be? The cracks are only in the back section of the house, I am guessing the back section was an add-on at some point. One crack is on the ceiling drywall and is pretty long in length. The other one is the ceiling and wall coming apart where they meet. It almost looks like somebody tried to caulk it at some point...