I need assistance in the process for solving this question. Which equation do I use?

I need assistance in the process for solving this question. Which equation do I use? Any information would be greatly appreciated.

1. Provide a line-by-line solution for the molecular speed of each of the following five gases at 300K: CO, SF6, H2S, Cl2, HBr. Finally, use these speeds to help place the five gases in order of increasing average molecular speed i.e. lowest to highest speeds.