suggestions? toliet/sink problem

[maintenanceguy]

hey im not really a plumber but can handle myself. so my problem is i have a sink that backflows to the toliet in a private bathroom in a office setting. when you run the sink air bubbles pop up in the toliet. then went to flush the toliet and it overflowed. i think that means theres a clog in there and my question is should i snake the sink or toliet or both? or is there something else that i should do?

 

[Caduceus]

If there is a building trap for the whole building drain, check that first to be snaked if it is clogged. If there is no trap for the building drain, lift the toilet and snake the drain down stream of it.

 

[Caduceus]

I should mention that this is if you are on the main/first floor. If you are on an upper level, it may be best to just lift the toilet and snake the drain from there. Be sure to run plenty of water in the sink while augering and continue after the drain opens to be sure the clog didn't just move down stream.