# Thread: Probability HW help

1. ## Probability HW help

I need help with these problems. I worked them out, got answers, and checked the back of the book to see if I got them correct.

A pair of six-sided balanced dice are rolled. What are the probabilities of getting the sum
of the face values as follows?
(a) 8
(b) 6 or 9
(c) 3, 8, or 12
(d) Not an even number

So I know the sample space is 36.
For (a) I got P = 5/36 b/c only 5 outcomes: (2,6) (3,5) (4,4) (5,3) (6,2) sum up to 8
For (b) I got P = 9/36
For (c) I got P= 8/36
For (d) I got P = 18/36 = 1/2

However, the book gives me these answers:

(a) 5/36
(b) 5/36
(c) 4/8
(d) 3/8

Am I doing something wrong?

2. ## Re: Probability HW help

Your answers are all correct (though you could reduce some of them to simpler fractions). The book’s answers for (b), (c) & (d) are patently incorrect.

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