Question

If you roll a pair of fair dice, what is the probability of : a) getting a sum of 2? b) getting a sum of 8? c) getting a sum of 13?

Answer 1

A pair of fair dice are rolled.

So, as each dice can have any of the six outcomes 1,2,3,4,5,6, so the number of apossible outcomes is

Question a

We can get a sum 2, only if the outcome is (1,1).

So, there is only 1 favourable case.

So, the probability is

Question b

We can get a sum of 8, if the outcomes are

(2,6), (3,5), (4,4), (5,3), (6,2).

So, there are 5 favourable cases.

So, the probability is

Question c

Now, the maximum sum that we can get on rolling two dices is 12, for the maximum outcome on each dice is 6.

So, the probability of getting a sum of 13 is 0, as it is an impossible event.