00:01
We're going to roll two fair dice and we first want to write down what the sample space is.
00:07
So if your first roll is a 1, then you can roll a 1 and a 1, a 1 and a 2, a 1 and a 3, and so forth.
00:18
Now let's write the outcomes if your first roll was a 2, if your first roll was a 3, first roll is a 4, first roll is a 5, and first roll is a 6.
00:47
So your sample space has 36 possible outcomes.
00:56
Now we want to, so this is part one, now we want to figure out the probability that the two numbers are the same.
01:08
So out of those 36, we have a 1 and a 1, a 2 and a 2, 3 and a 3, 4 and a 4, 5 and a 5, 6 and a 6.
01:18
So our probability is 6 out of 36 or 1 -6.
01:29
Now we want to know the probability that the two numbers differ by 2.
01:42
So let's count those outcomes.
01:46
So 2 apart would be a 1 and a 3, that will also be a 3 and a 1.
01:54
Differ by 2 would be a 2 and a 4, so that would be a 4 and a 2, 3 and a 5, and that would be a 5 and a 3, a 4 and a 6, and that would be a 6 and a 4.
02:13
So let's count those.
02:15
1, 2, 3, 4, 5, 6, 7, 8.
02:19
That's going to be 8 out of 36, and we're just going to reduce that...