The problem: A capacitor has the capacitance 35nF, the tolerance is max 10V. You have to put 30V over the capacitor . How many capacitors of same kind do you need if you want to achieve same C(35nF) that tolerate 30V? I have translated it from swedish to english, sorry if my english isn't so good, I hope you understand the though. Hypothesis: Has it something to do with the connection, serial or parallel? I think that the charge Q should be the same for the new connection therefore we should use parallel connection. Am I wrong?