Starting with the top 3 digit number, the first digit increases by 2 as you descend, from 1 to 11. The middle digit decreases by 1 each time, and the right hand digit alternates between 5 and 3.
In an election between two Chedi Singh and Chulbul Pandey, Chedi Singh got 55% of the total valid votes, 20% of the votes were invalid. If the total number of votes was 85000, the number of valid votes that Chulbul Pandey got, was :