Solving Capacitor Problem - Find q1

[Tcat]

Capacitor Problem!

Hi I have a problem where the applied potential is V_ab, Capacitors C1 and C2 are in parallel, and the combination is in series with C3. Now I'm trying to find the charge q1 on the capacitor C1. I thought that q1 = V_ab*((C3*C1*C2)/(C3 + C2+ C1)), but it is wrong. Can someone help me out? Thank-you so much!

 

[mukundpa]

In very first look it appears that you have calculated equivalent capacitance wrongly because the expression is dimensionally(units) incorrect.