Two capacitors `A` and `B` with capacities `3muF` and `2muF` are charged to a potential difference of `100 V` and `180V`, respectively. The plates of the capacitors are connected as show in figure with one wire of each capacitor free. The upper plate of `A` is positive and that of `B` is negastive. An uncharged `2muF` capcitor `C` with lead wires falls on the free ends to complete the circuit. Calculate
a. the final charge on the three capacitors.
b. the amount of electrostatic energy stored in the system before and after completion of the circuit.