A number is selected at random from the first 30 natural numbers. What is the probability that the number is a multiple of either 4 or 15? Choices:
A) 17 / 30
B) 2 / 5
C) 3 / 10
D) 4 / 15
E) 11 / 30

Rationale: number of multiples of 4 from 1 through 30 = 30 / 4 = 7 number of multiples of 15 from 1 through 30 = 30 / 15 = 2 number of multiples of 4 and 15 both from 1 through 30 = number of multiples of 15 * 4 ( = 60 ) = 0 total favourable cases = 7 + 2 - 0 = 9 probability = 9 / 30 = 3 / 10 answer : option c
Answer: C