Explanation
Since 60% of the registered population voted, 40% of that population did not. So the ratio of voters to nonvoters was 60%:40%. Divide both numbers in this ratio by 20% to reduce the ratio.
\(60 \% \div 20 \%=3 \text { and } 40 \% \div 20 \%=2\)
The ratio reduces to 3:2.