Probability

Question

Two fair dice are rolled. What is the probability that the sum is 4, given that at least one of the numbers rolled is even?

Answer 1

There are 6 numbers on each die, so there at 36 different combinations that can be rolled.  Each is just as likely as any other.

 

So how can you make 4?  3 ways:  1/3, 2/2, and 3/1.  But only one of these has an even number.  Since there is 1 roll that meets the requirements, the probability is 1/36.

 

 

Answer 2

with 2 fair dice, the probable total outcome is 36 (6*6).

 

now for the sum to be 4, then it's either (1,3)(2,2)(3,1), however we have been told that at least one number must be even, so the only probable is (2,2)..that is die 1 shows 2 and die 2 shows 2 or vice versa which is still same.

 

so 1/36

 

Answer 3

See other answers.