Droop quota / Hare quota

In pro-rep electoral systems the realistic quota to win a seat versus the theoretical quota. If there are three seats to be won in an election then in theory a quota of 33.3% of the vote (Hare) is needed to win every seat. However in practice, once a candidate has won 25% [100/(3+1)] of the vote, plus one more actual vote, he/she is granted a seat because it is then impossible for three further candidates to also win seats.