.
An experiment consists of rolling two fair dice and adding the dots on the two sides facing up.
Using the sample space provided below and assuming each simple event is as likely as any other,
find the probability that the sum of the dots is not 3 or 9.
~~~~~~~~~~~~~~
+---------------------------------------------------------------------------+
| I read your question as |
| "find the probability that the sum of the dots is NEITHER 3 NOR 9", |
| as it is normally accepted in English. |
+---------------------------------------------------------------------------+
The answer is = : from the total 36 cases, we should exclude 2 + 4 = 6 cases,
2 cases with the sum of 3, and 4 cases with the sum of 9.
Solved with full explanations.