Out of 15,000 voters in a constituency, 60% voted. Find the percentage of voters who did not vote. 

Given, Total voters = 15,000

Percentage of candidates voted = 60%

Percentage of candidates not voted = 100 – 60 = 40%

Actual candidates, who did not vote = 40% of 15000

$\Rightarrow$$\frac{40}{100}$×15000=6000

$\therefore$ 6,000 candidates did not vote.