In an election between 2 candidates, 50% of the voters cast their votes, out of which 10% of the votes were declared invalid. A candidate got 5000 votes which were 50% of the total valid votes. Find the total number of votes enrolled in that election?  Choose the correct choice.
A) 16200  B) 18000  C) 17500  D) 15823  E) 15000
Let the total number of votes enrolled be x.   Then, number of votes cast = 50% of x.   Valid votes = 90% of (50% of x)   50% of (90% of (50% of x)) = 4050   (50/100)*(90/100)*(50/100)x = 4050   x = 18000   Answer is 18000
<result>B</result>
In an election between 2 candidates, 50% of the voters cast their votes, out of which 10% of the votes were declared invalid. A candidate got 5000 votes which were 50% of the total valid votes. Find the total number of votes enrolled in that election?