If a number is chosen at random from the following list, what is the probability that it is not prime? 2, 3, 5, 7, 11, 13, 17, 19

Expert Answers
hala718 eNotes educator| Certified Educator

We have the numbers:

2, 3, 5, 7, 11, 13, 17, 19

The prime number is an integer that is dividible by 1 and itself only.

We notice that all the abpve numbers are prime numbers.

Then the probability of getting a prime = 8/8 = 1

This is called a certain event.

The probability of getting a number that si NOT a prime = 0/8= 0

This is called an impossible event.

neela | Student

The list numbers  given is: 2,3,5,7,11,13, 17 and 19.

The number of numbers are 8.

Each of these numbers are prime.

So the number of choices to make in a random choice = 8.

Since all  the 8 numbers given in this list ,  2,3,5,7,11,13 , 17 and 19,  are primes, we are sure that any number chosen is a prime number.

Therefore number of favourable choices = 8.

The number possible choices is 8.

Therefore the probability that a chosen number from the list at random (or otherwise) is a prime = 8/8 = 1.