Final answer:
The probability that the sum of the numbers rolled on two number cubes will be 5 is 1/9, as there are 4 favorable outcomes out of 36 possible combinations when rolling two dice.
Step-by-step explanation:
To calculate the probability that the sum of the numbers rolled on two number cubes will be 5, we need to consider all possible combinations of rolls that could result in a sum of 5. If we denote the number cubes as die A and die B, here are the possible combinations:
(1, 4)
(2, 3)
(3, 2)
(4, 1)
There are 4 favorable outcomes. Since each die has 6 faces, there are a total of 6 × 6 = 36 possible outcomes when rolling two dice. Therefore, the probability is 4/36, which simplifies to 1/9. The correct answer is B. 1/9.