An unbiased six-faced dice whose faces are marked with numbers 1, 2, 3, 4, 5,…
2026
An unbiased six-faced dice whose faces are marked with numbers 1, 2, 3, 4, 5, and 6 is rolled twice in succession and the number on the top face is recorded each time. The probability that the sum of the two recorded numbers is a prime number is....?
- A.
3/36
- B.
13/36
- C.
15/36
- D.
19/36
Attempted by 4 students.
Show answer & explanation
Correct answer: C
There are 6 x 6 = 36 equally likely ordered outcomes when the die is rolled twice. The possible prime sums are 2, 3, 5, 7 and 11. Their counts are: sum 2 -> 1 outcome, sum 3 -> 2 outcomes, sum 5 -> 4 outcomes, sum 7 -> 6 outcomes, and sum 11 -> 2 outcomes. Thus the number of favourable outcomes is 1 + 2 + 4 + 6 + 2 = 15. Therefore the required probability is 15/36. Hence option C is correct.
A video solution is available for this question — log in and enroll to watch it.