Katrina rolls a pair of six-sided number cubes with numbers 1 to 6. What is the probability that the sum of the numbers rolled is either an even number or a multiple of 3?

A. 3/4

B. 1/6

C. 2/3

D. 5/6

The correct answer is C since it asks for a probability of the sum being a even number or a multiple of 3. We have to use addition to solve this.

The sums that can be a even number are 2 + 2, 4 + 4, and 6 + 6. That makes 3/6, but simplified, it is 1/2.

Since the only number you can select that is a multiple of 3 is 6, that makes 1/6, which does not need to be simplified.

Now, we have to add these.

3/6 (1/2) + 1/6 = 4/6.

When simplified, it makes 2/3.