Roll a dice twice. What’s the probability that The sum of both dice is equal to 4 or that both die land on the same number
To find the probability, we need to determine the number of favorable outcomes and the total number of possible outcomes.
Total number of possible outcomes when rolling a dice twice:
Since there are 6 possible outcomes when rolling a single die, the total number of possible outcomes when rolling a dice twice is 6 * 6 = 36.
Number of favorable outcomes:
To get a sum of 4, the possible outcomes are (1, 3), (2, 2), and (3, 1). So there are 3 favorable outcomes.
To get both dice landing on the same number, the possible outcomes are (1, 1), (2, 2), (3, 3), (4, 4), (5, 5), and (6, 6). So there are 6 favorable outcomes.
However, we have counted (2, 2) twice, as it satisfies both conditions. So, we need to subtract 1 from the total.
Total number of favorable outcomes = 3 + 6 - 1 = 8
Probability = (Total number of favorable outcomes) / (Total number of possible outcomes)
Probability = 8 / 36
Probability ≈ 0.2222