if you want to rank up you shouldnt duo with someone a tier lower
unless they are smurfing but then your kinda a d bag.. (i see this all the time this is just an example) gold 2 player was duoing with a silver 2 http://gyazo.com/acd92e15af46102944fe72f1b288d611 guess what? they both dropped a division because the silver player couldnt keep up, when he was in my game it was the most uselss lee sin every while there team gets fed and the gold does nothing, his games are 3-14 3-8 ect duoing with lower ranks doesnt get you elo unless they are smurfing