Complex sentence: If there are "n" candidates, then there will be 2 "n" possible outcomes for a voter's ballot, it is also possible for the voter to vote for all of the candidates or none of them.
Split into simpler sentences: If there are "n" candidates, then there will be 2 "n" possible outcomes for a voter's ballot. It is also possible for the voter to vote for all of the candidates or none of them.