Multiple choice

Three different dice are rolled simultaneously three times. The probability that all of them show different numbers only two times, is equal to

  1. $100/729$
  2. $2/3$
  3. $100/243$
  4. $175/324$
Reveal answer Fill a bubble to check yourself
D Correct answer
AI explanation

When three different dice are rolled, the probability that they show different numbers is 6/6 * 5/6 * 4/6 = 5/9. The probability that they do not all show different numbers is 1 - 5/9 = 4/9. Using the binomial distribution for exactly 2 successes in 3 trials, the probability is 3C2 * (5/9)^2 * (4/9)^1 = 3 * 25/81 * 4/9 = 300/729. Simplifying the fraction by dividing the numerator and denominator by 9 gives the result 175/324.