Answered

William has a pair of identical number cubes. the faces of each cube are numbered 1 through 6. william will roll the cubes one time. what is the probability that the numbers showing face-up after the roll will have a sum of 9?

a.1/18b.1/9c.3/4d.8/9

Verified Answer :

The chances will be : 3 and 6 and 4 and 5
The probability of getting a sum of 9 would be 2/9

Answer:

Hence,  the probability that the numbers showing face-up after the roll will have a sum of 9 is:

1/9

Step-by-step explanation:

William has a pair of identical number cubes. the faces of each cube are numbered 1 through 6.

Now when he rolls two cubes together the possible outcomes are:

(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)

Now, the outcomes having sum 9 is:

(3,6) (6,3) (5,4) (4,5)

Hence total outcomes=36

Number of outcomes having sum 9 ( Number of favorable outcomes)=4

Hence,

Probability( sum is 9)=Number of favorable outcomes/Total outcomes.

                                 = 4/36=1/9

Hence, the answer is:

1/9

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