Question

When a pair of fair dice are rolled, what is the probability that the sum of the dice is 8, given the outcome is not 7

Answer 1

1/6

Explanation:

There are 36 possible outcomes.

Of those 36, there are 6 that add up to 7:

1+6, 2+5, 3+4, 4+3, 5+2, 6+1

That means there are 30 outcomes that don't add up to 7.

Of those 30 outcomes, there are 5 that add up to 8:

2+6, 3+5, 4+4, 5+3, 6+2

So the probability is 5/30 = 1/6.