a number is selected at random from the first 30 natural numbers . what is the probability that the number is a multiple of either 2 or 19 ?
"number of multiples of 2 from 1 through 30 = 30 / 2 = 15 number of multiples of 19 from 1 through 30 = 30 / 19 = 1 number of multiples of 2 and 19 both from 1 through 30 = number of multiples of 19 * 2 ( = 38 ) = 0 total favourable cases = 15 + 1 - 0 = 16 probability = 16 / 30 = 8 / 15 answer : option d"
divide(add(floor(divide(30, 2)), divide(30, 19)), 30)