Probability

Question

You want to find the probability of rolling a sum of 10 on two dice and then rolling a sum of 9 on the next roll. Tell whether these events are independent or dependent. Calculate the probability.

Answer 1

These events are INDEPENDENT because the first has no influence on the second--it's just the same to dice, randomly shaken out each time.

 

P(sum is 10) is = 3/36 = 1/12...because only pairs (4,6), (5,5) and (6,4) total up to ten.

P(sum 9) is 4/36 = 1/9.

 

The probability of the first event occurring, then followed by the second event, is the product of the above two results.