Which of the following shows the correct calculation for finding the probability of rolling two number cubes and getting a sum of 6 or 11?(1 point)

Responses

536 ⋅236
Start Fraction 5 over 36 End Fraction times Start Fraction 2 over 36 End Fraction

636 ⋅236
Start Fraction 6 over 36 End Fraction times Start Fraction 2 over 36 End Fraction

636 +236
Start Fraction 6 over 36 End Fraction plus Start Fraction 2 over 36 End Fraction

536 +236

1 answer

To find the probability of rolling two number cubes (dice) and getting a sum of 6 or 11, we first need to calculate the probabilities of each of these sums separately and then combine them.

Step 1: Calculate the total possible outcomes when rolling two dice.

  • There are \(6\) faces on each die, so the total number of outcomes when rolling two dice is \(6 \times 6 = 36\).

Step 2: Determine the number of outcomes for each sum.

  • Sum of 6: The combinations that give a sum of 6 are:

    • (1, 5)
    • (2, 4)
    • (3, 3)
    • (4, 2)
    • (5, 1)

    This gives us a total of 5 combinations for a sum of 6. Therefore, the probability of a sum of 6 is: \[ \frac{5}{36} \]

  • Sum of 11: The combinations that give a sum of 11 are:

    • (5, 6)
    • (6, 5)

    This gives us a total of 2 combinations for a sum of 11. Therefore, the probability of a sum of 11 is: \[ \frac{2}{36} = \frac{1}{18} \]

Step 3: Combine the probabilities for sums of 6 and 11. The total probability of getting a sum of 6 or 11 is the sum of the individual probabilities: \[ P(6 \text{ or } 11) = P(6) + P(11) = \frac{5}{36} + \frac{2}{36} = \frac{7}{36} \]

Now we evaluate the answer choices based on this calculation:

  1. \( \frac{5}{36} \cdot \frac{2}{36} \) - This is a multiplication of probabilities, which is incorrect.
  2. \( \frac{6}{36} \cdot \frac{2}{36} \) - This is also incorrect.
  3. \( \frac{6}{36} + \frac{2}{36} \) - This is incorrect since \( \frac{6}{36} \) is not the correct probability for a sum of 6.
  4. \( \frac{5}{36} + \frac{2}{36} \) - This matches our calculation for the sum probs, but this option is not listed correctly.

None of the options provided in the responses accurately reflect the addition of \( \frac{5}{36} + \frac{2}{36} \).

However, based on the closest patterns, if discussed in fundamentals, the correct calculation should be represented by: \( \frac{5}{36} + \frac{2}{36} \), which isn't explicitly there, but if you had to choose, the one that shows addition would be the most aligned: \( \frac{6}{36} + \frac{2}{36} \) if viewed simply as a structure.

So, choose accordingly based on the sum basics mentioned here.