I have tried to grasp the concept of calculating the RMS/Impedance for my sub. But I am not sure how much power my sub is being fed (obviously a professional installed it)

My Sub +++
JL Audio 10w3d (1)
It is a dual voice coil
It is suppose to recieve around 250 RMS
It is currently wired at 3 ohms

My Amp +++
RF p3002
» 2-channel car amplifier
» 75 watts RMS x 2 at 4 ohms (150 watts RMS x 2 at 2 ohms)
» 300 watts RMS x 1 bridged output at 4 ohms (4-ohm stable in bridged mode)
» variable high- and low-pass crossovers (40-400 Hz at 12 dB/octave)
» variable Punch Bass (0-18 dB boost at 45 Hz) with wired remote
» Tri-way capable (Tri-Way Crossover required)
» MOSFET power supply and output devices
» fuse rating: 40A x 1

Thanks