Six or Five

Two fair dice are thrown. What is the probability that the score on the first die is 6 or the score on the second die is 5?

I think these two events are not mutually exclusive.

Let S = 6

Let F = 5

P(S or F) = P(S or F) = P(S) + P(F) − P(S and F)

There is one 6 and one 5 per die.

P(S) = 1/6

P(F) = 1/6

P(S) + P(F) = 1/6 + 1/6

P(S and F) = 1/6 • 1/6

P(S or F) = 1/6 + 1/6 - 1/36

P(S or F) = 2/6 - 1/36

LCD = 36

P(S or F) = 12/36 - 1/36

P(S or F) = 11/36

 

correct

 

After Calculus 3, we dive into the world of probability, God willing.