SOLUTION: Two dice are rolled. Find the probability of getting the following. 2) a sum of 6 or 7 or 8 b) doubles or a sum of 4 or 6 c) a sum greater than 9 or less than 4, Please help me

Algebra ->  Probability-and-statistics -> SOLUTION: Two dice are rolled. Find the probability of getting the following. 2) a sum of 6 or 7 or 8 b) doubles or a sum of 4 or 6 c) a sum greater than 9 or less than 4, Please help me      Log On


   



Question 1097231: Two dice are rolled. Find the probability of getting the following.
2) a sum of 6 or 7 or 8 b) doubles or a sum of 4 or 6 c) a sum greater than 9 or less than 4,
Please help me answer this.

Answer by Edwin McCravy(20060) About Me  (Show Source):
You can put this solution on YOUR website!
Two dice are rolled.
Here are all possible rolls:  Count them, there are 36

(1,1) (1,2) (1,3) (1,4) (1,5) (1,6)

(2,1) (2,2) (2,3) (2,4) (2,5) (2,6)

(3,1) (3,2) (3,3) (3,4) (3,5) (3,6) 

(4,1) (4,2) (4,3) (4,4) (4,5) (4,6) 

(5,1) (5,2) (5,3) (5,4) (5,5) (5,6)

(6,1) (6,2) (6,3) (6,4) (6,5) (6,6)


Find the probability of getting the following.
2) a sum of 6 or 7 or 8
I'll color those red:

(1,1) (1,2) (1,3) (1,4) (1,5) (1,6)

(2,1) (2,2) (2,3) (2,4) (2,5) (2,6)

(3,1) (3,2) (3,3) (3,4) (3,5) (3,6) 

(4,1) (4,2) (4,3) (4,4) (4,5) (4,6) 

(5,1) (5,2) (5,3) (5,4) (5,5) (5,6)

(6,1) (6,2) (6,3) (6,4) (6,5) (6,6)

Count the red ones.  I count 16.  So the probability
of rolling one on those 16, is 16 times out of 36,
or 16/36 which reduces to 4/9.

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b) doubles or a sum of 4 or 6
I'll color those red:

(1,1) (1,2) (1,3) (1,4) (1,5) (1,6)

(2,1) (2,2) (2,3) (2,4) (2,5) (2,6)

(3,1) (3,2) (3,3) (3,4) (3,5) (3,6) 

(4,1) (4,2) (4,3) (4,4) (4,5) (4,6) 

(5,1) (5,2) (5,3) (5,4) (5,5) (5,6)

(6,1) (6,2) (6,3) (6,4) (6,5) (6,6)

Count the red ones.  I count 12.  So the probability
of rolling one on those 12, is 12 times out of 36,
or 12/36 which reduces to 1/3.

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c) a sum greater than 9 or less than 4,
Now you can do that one by yourself, right?

Edwin