In an election, candidate x got 70% of the overall valid votes. If 20% of the overall votes were declared invalid and the total numbers of votes is 640000, then find the number of valid votes polled in favour of the candidate.

358400

70% =  \(\frac{7}{10}\)  &  20% =  \(\frac{1}{5}\)

Number of valid votes =  \(\frac{4}{5}\) × 64000 = 51200

Votes in favor of candidate =  \(\frac{7}{10}\) × 51200 = 35840