My question is whether is the sum of the energies on each capacitor is equal to the energy on the equivalent capacitor? (this is in respect to capacitors in series however it could extend to those in parallel as well). Here is the problem I am working on. I have worked it using the hint and got the right answer but can't for the life of me get the same energy using the equivalent capacitance. Since the equivalent capacitor should be identical to the two capacitors should it not also have the same energy?