pg 595 For the experiment of rolling an ordinary pair of dic

pg 595

For the experiment of rolling an ordinary pair of dice find the probability that the sum will be each of the following.

Odd or greater than nine.

Solution

Well, the lowest the sum can be is 2, and the highest is 12

1 and 1 = 2
1 and 2, or 2 and 1 = 3
1 and 3, or 3 and 1, or 2 and 2, = 4
.......

6 and 6 = 12

Count the number of times each sum happens, 2 only happens in 1 of 36 possible scenarios, 3 happens in 2. Just divide cardinalities and you\'ll get what you need.

To find the probability that the sum will be odd or greater than 9

You need to find the sum for all cases that the sum is 3,5,7,9,10,11,12

3 = 2 ways
5 = 4 ways
7 = 6 ways
9 = 4 ways
10 = 4 ways
11 = 2 ways
12 = 1 way

odd or greater than 9 = 23/36