Equivalent capcitance of \(C_{2}\) and \(C_{3}\) 

\(C^{\prime}=\frac{C_{2} C_{3}}{C_{2}+C_{3}}=\frac{3 \times 6}{3 \times 6}\, \mu F=2\, \mu F\)

Common potential diference to \(C_{1}\) and \(C^{\prime}\) combined. 

\(v^{\prime}=\frac{C_{1} v_{1}+0}{C_{1}+C^{\prime}}=\frac{60}{1+2}=3\) volts

Charge of \(C_{2}, C_{3}\) system \(=C^{\prime} v=2 \times 20=40\, \mu C\)