Winning candidate received 11,400 votes, which is (60%) of the valid votes.
Let total valid votes be (V).
60% of V=11,400
10060V=11,400
V=6011,400×100=19,000
So, total valid votes (= 19,000).
Since (5%) votes were invalid, valid votes are (95%) of total votes cast.
Let total votes cast be (C).
95% of C=19,000
C=9519,000×100=20,000
Now, (80%) of eligible voters cast votes.
Let total eligible voters be (E).
80% of E=20,000
E=8020,000×100=25,000
25,000