Question

Two fair dice are rolled together. The probability that the sum of the numbers shown is 9 is

• A. 1/6
• B. 1/9
• C. 1/12
• D. 1/8

Hint:

Count ordered pairs that total 9 out of 36 equally likely outcomes.

Answer 1

The Correct Option is B

Step 1: List pairs adding to 9.
Only pairs from $\{3,4,5,6\}$ work: $3+6,4+5,5+4,6+3$.
Step 2: Divide by 36.
$\dfrac{4}{36}=\dfrac{1}{9}$.
\[\boxed{\dfrac{1}{9}}\]