A number is selected at random between 20 and 30, both numbers inclusive. Find the probability that the number is a prime
Answer Details
To solve this problem, we need to first determine the set of possible numbers that could be selected at random between 20 and 30. Since the problem states that both 20 and 30 are inclusive, the set of possible numbers is:
{20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30}
To find the probability that the selected number is prime, we need to determine the number of prime numbers in the set of possible numbers, and then divide that by the total number of possible numbers.
Prime numbers are numbers that are only divisible by 1 and themselves. The prime numbers in the set of possible numbers are:
{ 23, 29 }
Therefore, the probability that the selected number is prime is 2/11 or approximately 0.18.