What is the probability that an integer selected from the set of integers (20, 21, ...., 30) is a prime number?
A
2/11
B
5/11
C
6/11
D
9/11
E
2/3
Verified Correct Answer: A.
Step-by-Step Mathematical Solution
S = {20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30}
n(S) = 11
P = {23, 29}
n(P) = 2
Prob(P) = \(\frac{2}{11}\)
Source: Myschool Past Questions Archive (Record #23230)