Looking at Pentakill team comp.
tanky mid range
Sona initiate
mord-olaf-yorick rush enemy carries and establish front line.
Sona and karthus mop up
edit: ugh.... solo queue headache. It's like common sense disappears in solo-rank queue. If this is what people have to go through to get to the "good tier" then no wonder talks of ELO hell happens.