Question

An ordinary (fair) die is a cube with the numbers 1 through 6 on the sides (represented by painted spots). Imagine that such a die is rolled twice in succession and that the face values of the two rolls are added together. This sum is recorded as the outcome of a single trial of a random experiment.

Compute the probability of each of the following events:

Event : The sum is greater than 8 .
Event : The sum is divisible by 3 or 4 (or both).
Write your answers as exact fractions.....

Answer 1

10/36

Answer 2

what about the second event

Answer 3

20/36

Answer 4

Are you sure about that? I think it's 6/36 for a and 12/36 for b.

To get greater than 8, you need a sum of 9, 10, 11, or 12.
You can get this with:
3-6
4-5
4-6
5-5
5-6
6-6
So, 6 of 36 possible combinations.

For b, you can have a sum of 3, 4, 6, 8, 9, 12:
1-2
1-3
2-2
1-5
2-4
3-3
2-6
3-5
4-4
3-6
4-5
6-6
So, 12/36.

Or I missed something.

Answer 5

Simplifies to 1/6 and 1/3.