Information about one die
Topic: Random experiments and probability · more questions on this topic
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Two fair dice are thrown in order.
Find the probability that the second face is 3, given that the sum is 6.
Find the probability that the first face is 3 and the second face is not 3.
Worked answer (click to show)
The pairs with sum 6 are (1,5),(2,4),(3,3),(4,2),(5,1). Exactly one of the five has second coordinate 3, so the conditional probability is 1/5.
The faces are independent, so the probability is (1/6)\times(5/6)=5/36.