A number is selected at random between 20 and 30, both numbers inclusive. Find the probability that the number is a prime
A
\(\frac{2}{11}\)
B
\(\frac{5}{11}\)
C
\(\frac{6}{11}\)
D
\(\frac{8}{11}\)
Verified Correct Answer: A.
Step-by-Step Mathematical Solution
Possible outcomes are 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30. Prime numbers has only two factors
itself and 1
The prime numbers among the group are 23, 29. Probability of choosing a prime number
= \(\frac{\text{Number of prime}}{\text{No. of total Possible Outcomes}}\)
= \(\frac{2}{11}\)
Source: Myschool Past Questions Archive (Record #31285)