Find charge on each spherical shell after joining the inner most shell outer most shell by a conducting wire. Also find charges on each surface.

Explanation

Let the charge on the innermost sphere be x.
Finally potential of shell 1= potential of shell 3
`:. (Kx)/R+(K(-2Q))/(2R)+(K(6Q-x))/(3R)=(Kx)/(3R)+(K(-2Q))/(3R)+(K(6Q-x))/(3R)`

`3x-3Q+6Q-x=4Q, 2x=Q , x=Q/2`
`:.` Charge on innermost shell `=Q/2` & Charge on outermost shell `=(5Q)/2`

Charge on middle shell `=-2Q`
`:.` final charge distribution is as shown in figure.