In an election, a total of 500000 voters participated. A candidate got 255000 votes which was 60% of total valid votes. What was the percentage of invalid votes :

Let the number of valid votes be x
Then,
60% of x = 255000
⇒ x = $$\left( {\frac{{255000 \times 100}}{{60}}} \right)$$
⇒ x = 425000
Number of invalid votes :
= (500000 - 425000)
= 75000
∴ Required percentage :
= $$\left( {\frac{{75000 \times 100}}{{500000}}} \right)$$    %
= 15%