00:01
You have a probability distribution with a positive 7 for winning 7, a negative 2 for losing 2, and the probability of each being 9 out of 36 and 27 out of 36 to 0 .25 and 0 .75 respectively.
00:26
If we roll a dice twice, our pairs are like 2, 2, 2, 4, 2, 6, 4, 4, 4, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, so there's 9 of those.
00:49
So we roll a die twice, we get 36 outcomes, so 9 out of 36 would be a pair of even numbers.
00:59
So our expected value is 7 times 0 .25 plus negative 2 times 0 .75 or 1 .75 plus negative 1 .5, which is 25 cents...