I think most people would snake from the sink (lav) first.
Then you can snake the tub through the overflow of the tub drain.
hi hope i can get some help..had a fire and am just finnishing up bathroom ..after 4 months of renovations...this is my last room..i installed tub and it drained no problem..but when i installed sink..dammit i think i might have overlooked checking drain pipe for forgien material..when i ran water it came up in the tub ..and now tub drains very slowly so ..no ostruction between those two ..but must have a plug where drain goes into main sewer line..please tell me there is a way to snake these lines ...the p trap for the tub has no drain ..so snaking from the tub my best bet???....i hope someone can help ..maybe drain cleaner???..this is a upper bath over the newly remodeled kitchen ...i am going to have a stroke over this problem one of many problems i have had during renovations ...as insurance company would not pay ..because of knob and tube wiring so beware anyone who has it ...a answer with hope would be gratly appreciated thanks mikee
Let not your heart be troubled, Mikee!!! You've made it through the fire and it sounds like you've about got the renovation licked. As Terry said, these drains can be snaked without too much of a problem.