Two capacitors of $2\mu Fand3\mu F$ are charged to 150V and 120V respectively. The plates of capacitor are connected as shown in the figure. An uncharged capacitor of capacity $1.5\mu F$ is connected to the free end of the wires as shown. Then:

We solve this question by using method of flow of charges. If a charge q flows in the closed loop in clockwise direction. Then final charges on different capacitors are as shown in figure below.

Writing the equation of potential drop in the loop we have $\frac{360-q}{3}+\frac{300-q}{2}-\frac{q}{1.5}=0$

Solving the above equation, we get $q=180\mu C$

Charge on  $2\mu F$ capacitor is $300-180=120\mu C$