Question

Two 6-sided dice are rolled. what is the probability that the sum of the two numbers on the dice will be greater than 9?

Answer 1

What combination of numbers are needed in order to get a sum of 9?
        It can be:
             •  First die is 6 , second die is 3 
             •  First die is 3 , second die is 6
             •  First die is 4 , second die is 5
             •  First die is 5 , second die is 4

How many possible combinations are made? Yep, 4 possible combinations.

Recall the formula for probability
       $Probability = \frac{Number of desired outcomes}{Number of all possible outcomes}$

There are 4 desired number of outcomes.
How about the total possible outcomes?
     • How many numbers are possible to appear when the first die is rolled?
        Answer: 6
     • What about the second die?
        Answer: Also 6
     • Therefore, total possible outcomes = 6 * 6 = 36 outcomes

You can now solve for the probability.

      $Probability = \frac{4}{36} = \frac{1}{9}$ or approximately 11.11%