The probability that a number selected at random from the numbers 21, 22,…

Step-by-Step Solution
To find the probability that a number selected at random from the range 21 to 40 (inclusive) is a prime number, follow these steps:

Determine the total number of outcomes:
The range is from 21 to 40 inclusive. The total count of integers is calculated as (40 - 21) + 1 = 20 integers.

Identify the favorable outcomes (prime numbers):
A prime number is a number greater than 1 that has no positive divisors other than 1 and itself. Within the range 21 to 40, the prime numbers are:

23

29

31

37
There are exactly 4 prime numbers in this range.

Calculate the probability:
The probability is the ratio of favorable outcomes to total possible outcomes:
Probability = (Number of Primes) / (Total Numbers)
Probability = 4 / 20
Probability = 1 / 5