technolog, or whoever you are -- your op was written early morning of 1-4, so the clog had to be there sometime late 1-3.three days on a drain clog. you must need a shower by now.
seriously -- you say that the kitchen sink is the same as the tub. possibly, some garbage has gathered in the kitchen trap, but it's not likely to happen at the same time. there must be a clog in the drain beyond where the tub and kitchen sink are attached to the main drain.a snake is likely needed.
call the landlord, if you don't have access to a snake.
when this is fixed, go to a buck store or a hardware and buy a strainer made for this purpose. it should be from 2 to 5 bucks. the landlord will gladly pay for this.as well, some preventive maintenance just makes sense -- drain cleaner in all of the traps every 2 months. in your case, seeing that wad of hair -- once a month.the landlord will be happy to pay for this,as well,since he won't have to come back for this reason.
stop "yapping" so much on the net, and get this fixed. three days -- and take a shower. good luck.