Math Problem Statement
Two dice are rolled with numbers 1-6. Find the probability that; (i) the sum is 13 (ii) the product is 6? (iii) the difference is 1 (iv) the pair of prime number (v) the sum is divisible by 3 or 5?
Solution
To solve this, we analyze the given scenarios based on the outcomes of rolling two dice. Each die has 6 faces numbered 1 through 6, and the total number of outcomes when rolling two dice is .
Now let's address each part of the problem.
(i) Probability that the sum is 13
- The highest possible sum from rolling two dice is 12 (6 + 6).
- Since 13 is not achievable, the probability of getting a sum of 13 is .
(ii) Probability that the product is 6
We need to identify the pairs of numbers from the two dice whose product equals 6. The pairs are:
- (1, 6)
- (2, 3)
- (3, 2)
- (6, 1)
These are 4 favorable outcomes out of 36 total outcomes, so the probability is:
(iii) Probability that the difference is 1
We want the difference between the two dice to be 1. The possible pairs are:
- (2, 1), (3, 2), (4, 3), (5, 4), (6, 5)
- (1, 2), (2, 3), (3, 4), (4, 5), (5, 6)
There are 10 favorable outcomes, so the probability is:
(iv) Probability of rolling a pair of prime numbers
Prime numbers between 1 and 6 are 2, 3, and 5. We need to find the pairs where both dice show a prime number. The possible pairs are:
- (2, 2), (2, 3), (2, 5)
- (3, 2), (3, 3), (3, 5)
- (5, 2), (5, 3), (5, 5)
There are 9 favorable outcomes, so the probability is:
(v) Probability that the sum is divisible by 3 or 5
We need to check for sums that are divisible by either 3 or 5. The sums of two dice can range from 2 to 12.
- Sums divisible by 3: 3, 6, 9, 12
- Sums divisible by 5: 5, 10
Now, let's count how many outcomes give these sums:
- For sum = 3: (1, 2), (2, 1) → 2 outcomes
- For sum = 6: (1, 5), (2, 4), (3, 3), (4, 2), (5, 1) → 5 outcomes
- For sum = 9: (3, 6), (4, 5), (5, 4), (6, 3) → 4 outcomes
- For sum = 12: (6, 6) → 1 outcome
- For sum = 5: (1, 4), (2, 3), (3, 2), (4, 1) → 4 outcomes
- For sum = 10: (4, 6), (5, 5), (6, 4) → 3 outcomes
Adding them all together, we get favorable outcomes. Therefore, the probability is:
Final Results:
- Probability the sum is 13:
- Probability the product is 6:
- Probability the difference is 1:
- Probability of a pair of prime numbers:
- Probability the sum is divisible by 3 or 5:
Would you like more details or have any questions?
Here are 5 related questions to think about:
- What is the probability of getting an even product from two dice rolls?
- What is the probability that the sum of two dice is a prime number?
- How would the probabilities change if the dice had numbers 1-8 instead of 1-6?
- What is the probability of rolling a double (the same number on both dice)?
- How does the probability of rolling an odd sum compare to rolling an even sum?
Tip: Always break down complex probability questions by first identifying all possible outcomes and then counting favorable ones.
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Math Problem Analysis
Mathematical Concepts
Probability
Combinatorics
Formulas
Probability formula: P(Event) = (Number of favorable outcomes) / (Total number of outcomes)
Theorems
Basic probability theory
Prime number identification
Suitable Grade Level
Grades 6-8