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Question

Two dice are thrown simultaneously. The probability that the product of the numbers appearing on the top faces of the dice is a perfect square is

The correct answer is
2/9

Dice Probability: Product as Perfect Square

When two dice are thrown simultaneously, each die has 6 possible outcomes (numbers 1 through 6). The total number of possible outcomes is the product of the outcomes for each die.

Total possible outcomes = $6 \times 6 = 36$.

Identifying Favorable Outcomes

We need to find the outcomes where the product of the numbers on the two dice ($d_1 \times d_2$) is a perfect square. A perfect square is a number that is the square of an integer (e.g., 1, 4, 9, 16, 25, 36, ...).

Let's list the pairs $(d_1, d_2)$ such that $d_1 \times d_2$ is a perfect square, where $d_1, d_2 \in \{1, 2, 3, 4, 5, 6\}$:

  • If the product is 1: (1, 1)
  • If the product is 4: (1, 4), (4, 1), (2, 2)
  • If the product is 9: (3, 3)
  • If the product is 16: (4, 4)
  • If the product is 25: (5, 5)
  • If the product is 36: (6, 6)

The set of favorable outcomes is {(1, 1), (1, 4), (4, 1), (2, 2), (3, 3), (4, 4), (5, 5), (6, 6)}. The total number of favorable outcomes is 8.

Calculating the Probability

Probability is calculated as the ratio of the number of favorable outcomes to the total number of possible outcomes.

$ P(\text{Product is a perfect square}) = \frac{\text{Number of Favorable Outcomes}}{\text{Total Number of Outcomes}} $

$ P(\text{Product is a perfect square}) = \frac{8}{36} $

Simplifying the fraction gives:

$ \frac{8}{36} = \frac{2 \times 4}{9 \times 4} = \frac{2}{9} $

The probability that the product of the numbers appearing on the top faces of the dice is a perfect square is 2/9.

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Important Questions from Probability

  1. Two dice are thrown simultaneously. What is the probability of getting the same number on both the dice?

  2. The probability of being 53 Sundays in year 2020 is-

  3. Three dice are thrown randomly. The probability of coming 3 in at least one die is

  4. The probability of having 53 Tuesdays in an ordinary year is:

  5. When two dice are tossed simultaneously, the probability that the sum of the numbers appearing on both the dice is 8 will be

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