4/5th of the voters in Bellary promised to vote for
Sonia and the rest promised to vote for Sushma.
Of these voters, 10% of the voters who had promised to vote for Sonia, did not vote on the election
day, while 20% of the voters who had promised to
vote for Sushma did not vote on the election day.
What is the total no. of votes-polled if Sonia got
216 votes?
(a) 200
(c) 264
(b) 300
(d) 100
answer - 264

Let the total number of voters be 'T'
Number of voters who voted Sonia = (0.8)(0.9)T
Number of voters who voted Sushma = (0.2)(0.8)T
It is given,
0.72T = 216
T = 300
Number of votes who did not poll = T - (0.8)(0.9)T - (0.2)(0.8)T = 0.12T = 36
Total no. of votes polled = 300 - 36 = 264
Hope this helps!

Let total voters be x.
Voters for Sonia = 4x/5.
Voters for Sushma = x/5.
On election day,
Voters for Sonia = 4x/5 - 0.4x/5 = 3.6x/5
Voters for Sushma = x/5 - 0.2x/5 = 0.8x/5

Now,
3.6x/5 = 216
x = 216*5/3.6 = 300.

My answer comes out to be 300.