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Two number cubes are rolled. What is the probability of rolling a sum of 9 or a sum that is even?

User Amaan
by
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2 Answers

1 vote
two dice are thrown and the only possibilities are rolling 2-12. we are trying to find the probability of rolling a 2,4,6,8,9,10,12
7 out of 11 is the probability of rolling a 9 or an even
User Wattry
by
6.7k points
5 votes

Well I don't know !
Let's figure it out together.

Each cube can land in 6 different ways, so the total number
of possible results with two cubes is (6 x 6) = 36 .

Now we need to figure out how many of those 36 possibilities
meet your specifications ... either 9 or any even number.

Ways to make 9 :

3 . . . 6
6 . . . 3
4 . . . 5
5 . . . 4

Four ways to make 9.
____________________________

Ways to make an even number:

1 . . . 1
3 . . . 1
1 . . . 3
2 . . . 2
5 . . . 1
1 . . . 5
6 . . . 2
2 . . . 6
6 . . . 4
4 . . . 6
6 . . . 6

Eleven ways to make an even number.
_____________________

Total number of ways to succeed = (4 + 11) = 15 ways

So the probability of succeeding (rolling 9 or an even number)
is

15 / 36 = 5 / 12 = 0.41666... = (41 and 2/3) % .

User Tila
by
7.1k points