*The key aspect is RMS. Total power of a speaker is based upon what level it can reach at certain bursts. RMS is continuous power being sent. In this respect, there are many 200 watt speakers having a RMS of maybe 40. The goal is to match the speakers to the receiver.
A.) If the receiver is dumping 40 watts, one should obtain a speaker with 40 watts (RMS)- "Total power means nothing other than handling high or low frequency at upper levels > 'Fact, no physics here'.
No calculus here, just advanced math.