I am not disagreeing with what the EMG people are saying. The problem is that you do not seem to understand what they are saying and how it applies to your question.
Why should you need to have RMS explained any more. It isn't an explanation that you need. What you need to do is to use the definition to work out some numbers yourself. Douglis has given you a perfect worked example.
I cannot be bothered to answer that question because it is just a smoke screen to protect you from going to the trouble of working stuff out for yourself.