It got that. Highlighted in bold in the quoted text. Archived Message
Posted by GrandmotherPearlsJam on February 23, 2025, 14:02:43, in reply to "Rolling 3 dice and getting all the same is not 1/6... It's 6/216, or 1/36.*"
It got the same percentages as you.  Previous Message  Previous Message Let's calculate the probability of rolling **three of a kind** using **three dice** and **four dice** to determine how much the odds increase. ### **Case 1: Rolling 3 Dice** We need exactly **three** dice to show the same number. 1. Pick a number (1-6) that will be the triplet → Probability = \( \frac{1}{6} \). 2. The first die can be any number → Probability = \(1\). 3. The second die must match the first → Probability = \( \frac{1}{6} \). 4. The third die must also match → Probability = \( \frac{1}{6} \). Thus, the probability of rolling three of a kind exactly is: \[ 6 \times \left(\frac{1}{6} \times \frac{1}{6}\right) = \frac{6}{36} = \frac{1}{6} \approx 16.67\% \] ### **Case 2: Rolling 4 Dice** We need at least **three** of the four dice to show the same number. #### **Scenario 1: Exactly 3 Matching, 1 Different** 1. Pick the matching number (1-6) → \( \frac{1}{6} \). 2. Choose which three dice will match (ways to choose 3 out of 4) → \( \binom{4}{3} = 4 \). 3. The three matching dice each roll that number → \( \left(\frac{1}{6}\right)^2 \). 4. The fourth die rolls a different number (5 choices) → \( \frac{5}{6} \). \[ 6 \times 4 \times \left(\frac{1}{6} \times \frac{1}{6}\right) \times \frac{5}{6} = \frac{120}{1296} \approx 9.26\% \] #### **Scenario 2: All 4 Matching** 1. Pick the number → \( \frac{1}{6} \). 2. All four dice must roll that number → \( \left(\frac{1}{6}\right)^3 \). \[ 6 \times \left(\frac{1}{6} \times \frac{1}{6} \times \frac{1}{6}\right) = \frac{6}{216} = \frac{1}{36} \approx 2.78\% \] ### **Total Probability (Rolling 4 Dice)** Adding both scenarios together: \[ 9.26\% + 2.78\% = 12.04\% \text{ (extra chance with 4th die)} \] \[ 16.67\% + 12.04\% = 28.7\% \] ### **Odds Increase** \[ \frac{28.7\%}{16.67\%} \approx 1.72 \] So, rolling **4 dice instead of 3 increases your odds by about 72%** of rolling three of a kind.
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