+0  
 
0
110
1
avatar+30 

Four standard six-sided dice are rolled. What is the probability that the product of the numbers on the top faces of all four dice is a prime number? Express your answer as a common fraction.

 Jan 14, 2021
 #1
avatar+117576 
+2

Here's  my attempt :

 

The only  possible prime products are  2, 3  or  5

This  means that  3  of the  dice  must  show 1   and the  other  shows a 2, 3, or 5

 

The probability  is

 

Choose   any one of the  four dice to show  one of the primes *  probability of showing three 1s on three of the  dice *  probability of showing  one of the primes on the remaining  die = 

 

 C (4,1)  ( 1/6)^3  ( 3/6)  =  

 

1/  108

 

 

cool cool cool

 Jan 14, 2021
edited by CPhill  Jan 14, 2021

44 Online Users

avatar