Find the probability that a number selected from numbers 1, 2, 3,..., 20 is a prime number, when each of the given numbers is equally likely to be selected?  Choose the correct choice from the following:
A) 10/20  B) 1/20  C) 8/20  D) 3/20  E) 7/20
Let X be the event of selecting a prime number.   X = {2, 3, 5, 7, 11, 13, 17, 19}   n(X) = 8,   n(S) = 20   Hence, the required probability is 8/20.   ANSWER:8/20
<result>C</result>
Find the probability that a number selected from numbers 1, 2, 3,..., 20 is a prime number, when each of the given numbers is equally likely to be selected?