Out of first 20 natural numbers, one number is selected at random. The probability that it is either an even number or a prime number is -.
Answer: D
n(S) = 20
n(Even no) = 10 = n(E)
n(Prime no) = 8 = n(P)
P(EᴜP) = 10/20 + 8/20 - 1/20 = 17/20