Aptitude - Probability - Discussion
Discussion Forum : Probability - General Questions (Q.No. 10)
10.
Two dice are tossed. The probability that the total score is a prime number is:
Answer: Option
Explanation:
Clearly, n(S) = (6 x 6) = 36.
Let E = Event that the sum is a prime number.
| Then E | = { (1, 1), (1, 2), (1, 4), (1, 6), (2, 1), (2, 3), (2, 5), (3, 2), (3, 4), (4, 1), (4, 3), (5, 2), (5, 6), (6, 1), (6, 5) } |
n(E) = 15.
| P(E) = |
n(E) | = | 15 | = | 5 | . |
| n(S) | 36 | 12 |
Discussion:
64 comments Page 1 of 7.
Deepak said:
1 month ago
We get the number from the first dice = 1,2,3,4,5,6
And the same from the second dice.
We have prime numbers in both dice is 1, 2, 3, 4, 5 and a total of 1+2=3 is a prime number.
So, total 12.
We have 5 prime numbers and a total score number.
So, 5/12 is the answer.
And the same from the second dice.
We have prime numbers in both dice is 1, 2, 3, 4, 5 and a total of 1+2=3 is a prime number.
So, total 12.
We have 5 prime numbers and a total score number.
So, 5/12 is the answer.
Bini said:
2 years ago
The possible outcomes for the sum of two dice are as follows:
Sum: 2
Possible outcomes: (1, 1).
Sum: 3
Possible outcomes: (1, 2), (2, 1).
Sum: 5
Possible outcomes: (1, 4), (2, 3), (3, 2), (4,1).
Sum: 7
Possible outcomes: (1, 6), (2, 5), (3, 4), (4, 3), (5, 2), (6, 1).
Sum: 11
Possible outcomes: (5, 6), (6, 5).
So, there are 15 possible outcomes.
Sum: 2
Possible outcomes: (1, 1).
Sum: 3
Possible outcomes: (1, 2), (2, 1).
Sum: 5
Possible outcomes: (1, 4), (2, 3), (3, 2), (4,1).
Sum: 7
Possible outcomes: (1, 6), (2, 5), (3, 4), (4, 3), (5, 2), (6, 1).
Sum: 11
Possible outcomes: (5, 6), (6, 5).
So, there are 15 possible outcomes.
(3)
Riuhsi said:
3 years ago
2 is the prime number @Sabin Banset.
(2)
Sabin Basnet said:
3 years ago
When we add 1 and 1 it becomes 2.
So, 2 is not a prime number.
So, there is n(e) = 14 only
And 14/36 = 7/18.
That's all.
So, 2 is not a prime number.
So, there is n(e) = 14 only
And 14/36 = 7/18.
That's all.
(3)
Maths said:
3 years ago
1 is not a prime number.
So, the correct answer is 14/36 = 7/18.
So, the correct answer is 14/36 = 7/18.
Trisha said:
5 years ago
@Rutvik.
There (1,1) consider only once because there is no difference between 1, 1 or 1, 1, but there is always a difference between 2, 5 or 5, 2.
Suppose dice 1 and dice 2 have the same no. Like (1, 1) how will you differentiate dice 1 and 2 but if the no. Are change like (1, 2) (2, 1) or (5, 2) (2, 5) you will differentiate dice 1 and 2. That's why.
I hope now you will understand.
There (1,1) consider only once because there is no difference between 1, 1 or 1, 1, but there is always a difference between 2, 5 or 5, 2.
Suppose dice 1 and dice 2 have the same no. Like (1, 1) how will you differentiate dice 1 and 2 but if the no. Are change like (1, 2) (2, 1) or (5, 2) (2, 5) you will differentiate dice 1 and 2. That's why.
I hope now you will understand.
Anu said:
5 years ago
@Sowmya.
Yes, the total score here means the sum of numbers.
Yes, the total score here means the sum of numbers.
Priya said:
5 years ago
@All.
Why here we perform addition operation to get a Prime number? Instead of getting total as prime we use (product or subtract).
Why only addition is performed? Can anybody explain this clearly!
Why here we perform addition operation to get a Prime number? Instead of getting total as prime we use (product or subtract).
Why only addition is performed? Can anybody explain this clearly!
Ruthvik Gowda said:
5 years ago
Why (1, 1) conisdered only once ?
Since there is two dices we can get (1, 1) twice right, like this combination (2, 5) & (5, 2).
Since there is two dices we can get (1, 1) twice right, like this combination (2, 5) & (5, 2).
(2)
Sweta said:
5 years ago
Are 4 and 6 prime numbers?
4 and 6 divisible by not only 1 and itself, but it is also divisible by 2, 3.
4 and 6 divisible by not only 1 and itself, but it is also divisible by 2, 3.
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