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 :

Answer: Option C

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%