Charging two capacitors then putting them in parallel

[Linus Pauling]

1. Capacitors C_1 = 13 uF and C_2 = 26 uF are each charged to 20 V, then disconnected from the battery without changing the charge on the capacitor plates. The two capacitors are then connected in parallel, with the positive plate of C_1 connected to the negative plate of C_2 and vice versa.

Afterward, what is the charge on each capacitor?



2. Q = VC, equivalent C for parallel capacitors add linearly



3. I know Q1 and Q2 are 87 and 170 uC, respectively. I know that the equivalent capacitance is simple 39 uF. But I still don't see how these charges were obtained.

 

[rock.freak667]

The two capacitors are then connected in parallel, with the positive plate of C_1 connected to the negative plate of C_2 and vice versa.

If they are connected in parallel, what is the potential difference across each capacitor?