Understanding Charge Distribution in Electrostatic Systems

[vivekrai]

Homework Statement

http://u.spig.in/forum/105320795.jpg

Homework Equations

general Electrostats formulas

The Attempt at a Solution

I tried to solve the problem using Energy conservation ie., Change in PE = Work done. But that seem to yield wrong answer (1) while the correct answer is 2.

I had read a similar sum in Irodov's ' Basic Laws of Electromagnetism ' in which it was written that this method fails in above case. Please help me solving this.

 

[kushan]

did you make the final charge distribution in the system?

 

[vivekrai]

did you make the final charge distribution in the system?

What does that mean? Or How do I do it?