Potential between Different Charges

Example considers a positive charge of 3 C as shown in below figure.

As illustrated, the work to be done in moving some electrons. Suppose a charge of 1C might move three electrons. In Figure a then the charge of +3C may attract 9 electrons toward right.  Though, a charge of +1 C at the opposite side may attract 3 electrons towards left. The overall result then is that 6 electrons may be moved toward the right to the more positive charge.

In Figure b, one charge is 2C, whereas the other charge is neutral having 0C.For the difference of 2C, again 2*3 or 6 electrons may be attracted to the positive side.