What is the voltage across C2 in this circuit?

[jake jungle]

Homework Statement

Find the pd accros C2

Homework Equations

Q=CV

The Attempt at a Solution

i find C23 = (C2C3)/ (C2 + C3)
then find Q23 = V x C23
Q23 = Q2 = C2V2 => V2

i used this and got V2 = 15V , however the answer is 20V , and i even didnt use the data of C1 . am i wrong somewhere ?

 

[gneill]

Your answer looks fine, unless there are some initial conditions (such as initial charges) that weren't specified. C2 and C3 form a voltage divider which is across the supply 30 V, and since they are of equal capacitance they must must divide the voltage... how?