Question

What is the probability of getting either a sum of 6 or at least one 5 in the roll of a pair of dice?

Answer 1

What are the combinations for a sum of 6?

1,5

This is one way, what are the others?

What are the combinations for getting at least one 5?

5,1 is one way

What are the other ways?

Count the number of distinct pairs.

The number of possible pairs is 6*6.

To the probability is the number of distinct pairs divided by the number of possible pairs.

That's it!

Answer 2

for a sum of 6 theres 5,1 and 3,3
for at least one 5 theres 5,1 5,2 5,3 5,4 5,5 5,6

Answer 3

@ybarrap

Answer 4

That's right (also {4,2},{2,4} and {5,5} are possibilities), so the unique list combining the two lists are
5,1
1,5
3,3
4,2
2,4
5,2
2,5
3,5
5,3
4,5
5,4
5,6
5,5

We count 5,1 and 1,5, for example, as separate because there are 6*6 total combinations of dice, which includes both of these possibilities separately.

These are 13 unique possibilities.

So the probability is 13/36, which is about a 36.1% chance