You roll two fair dice a red one and a green one a What is t

You roll two fair dice, a red one and a green one.

a. What is the probability of getting a 4 on the red die or a 2 on the green one?

b. What is the probability of getting a 4 on one die (either one) and a 2 on the other?

c. Suppose we know that a 4 was rolled on one of the dice and a 2 was rolled on the other. What is the      probability that the 4 was rolled on the red die?

Solution

for each number you have a probability of 1/6 because you have 6 numbers un a dice

a)

P getting 4 on a red or 2 on the green one   =    1/6   +   1/6   = 2/6

b)

Probability = 2/12    +    2/12    = 1/3

c)

P( 4 was rolled on the red die ) =    1/6     /    2/6 = 0.5