capacitor again

After K is closed, C1 should be at the same potential as R1, C2 should be at the same potential as R2. (Because current flows along the resistors, not the capacitors.)

So, p.d. across C1 = 100/(100 + 200) X 12 = 4 V

p.d. across C2 = 12 - 4 = 8 V

Charge on C1 = C1V = (10)(4) = 40 uF

Charge on C2 = C2V = (20)(8) = 160 uF