In Fig, C1 = 6.00µF, C2 = 3.00µF, and C3 = 5.00µF. The capacitor network is connected

Question:

In Fig, C1 = 6.00µF, C2 = 3.00µF, and C3 = 5.00µF. The capacitor network is connected to an applied potential Vab. After the charges on the capacitors have reached their final values, the charge on C2 is 40.0 µC.
(a) What are the charges on capacitors C1 and C3?
(b) What is the applied voltage Vab?