Question

A black and a red die are rolled together. find the conditional probability of obtaining a sum of 8, given that red die resulted in a number less than 4

Answer 1

Answer:

3/5

Step-by-step explanation:

The formula for conditional probability is:

P(B|A) = P(A and B) / P(A)

The conditional probability of obtaining a sum of 8 is event A

          red

black    1     2   3    4    5   6  

            +     +   +    +    +     +

 1          

 2                                      8

 3                                  8

 4                           8

 5                     8

 6               8

= 5/36

The conditional probability of obtaining a red die resulted in a number less than 4

= 3/36

P(B|A) = P(A and B) / P(A)

= (3/36) / 5/36

= 3/5