A pair of dice is rolled. What is the probability that the sum is 9 or that the first number is a 2?

Question

mathmale · Answer

In how many ways could you obtain a sum of 9 through rolling two fair dice?
In how many ways could you obtain a 2 on the first die?
These events are completely independent.  
Using these facts, find P("sum is 9" OR "2 on the first die")  Which rule of probability applies here?

anonymous · Answer

Im not sure its a pre-test and my last question, Have no idea on the subject.

mathmale · Answer

James, a pre-test is given you for the purpose of finding out where you are NOW in terms of your knowledge.  If you haven't studied probability before and don't know what to do, that's OK; I assume you will learn that material in your next course.  Were I to explain the solution of this problem in depth, and you type in the answer, then we would have defeated the purpose of the pretest.