In an election contested between A and B, A obtained votes equal to twice the no. of persons on the electoral roll who did not cast their votes & this later number was equal to twice his majority over B. If there were 18000 persons on the electoral roll. How many voted for B.

Ans: Let x and y be the no. of votes for A & B respecatively.

APQ:

The no. of persons who did not vote = (18000 - x - y)

x = 2(18000 - x - y)

=> 3x + 2y = 36000 ---------------(1)

&

(18000 - x - y) = (2) (x - y)

=> 3x - y = 18000 ----------------(2)

On solving we get,   y = 6000 and x = 8000

Vote for B = 6000