# Find the odds of the outcome if an eight-sided dice is rolled: a prime number.

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### 3 Answers

We will assume that the 8-sided die has the numbers :

1 2 3 4 5 6 7 8

The prime numbers are : 2 3 5 7

Then the outcomes are 2 3 5 7

The probability of having a prime number if the die rolled once= 4/8=1/2.

The odds of the outcome if an 8 sided dice is rolled.

Solution:

The odds of the outcome if you roll a dice of 8 sides each with a number 1 to 8 are : One of the 8 faces coming up.

The odds in favour of a prime is 5 out of 8 , the primes are (1,2,3,5,and7).

So the probability of the odds in favour of prime is 5/8 in a rolling

It is assumed that the dice is marked with numbers 1 to 8, and the probability of getting any one of these number on a roll is equal.

That is probability of getting any number from 1 to 8 on a roll of dice = 1/8

There are four prime numbers between 1 and 8. These are 2, 3, 5, and 7.

The probability of getting a specific of these 4 prime number on a roll = 1/8

The probability of getting any one of the 4 prime numbers on a roll:

= Sum of probabilities of getting each of the four numbers

= 1/8 + 1/8 + 1/8 + 1/8 = 4/8 = 0.5

In other words odds of getting a prime number versus not getting a prime number are 1:1.