Guild Wars 2

hi i have a quick question

If drop 4 exotic chest armor in MF would i get a different random chest armor with different skin? any1 know

There is only one way to find out… Do it! >.<
I will pray for you xD

Dropping 4 of the same item in the Mystic Forge will result in that type of item as end result. So yes, using 4 chest armors will result in a chest armor (though be sure to use 4 heavy/medium/light armors if you want one of these specifically).
This does not guarantee a different skin though. You may end up with the same type of skin and different stats.

Could be more cost effective to just sell your 4 exotic chest armors and buy a different skin from the trade post. Just thought I would throw that out there.