Question

pair of dice is rolled once find the probability of getting :sum of two number is a prime number​

Answer 1

No. of total favourable outcomes :- 36

There are 6 number in each dice and it state the pair of dice is thrown once.

Therefore, 6 × 6 = 36

No. of favourable outcomes :- 15

• => 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

P(Sum of two no. is prime number) = No. of favourable outcomes/Total No. of favourable outcomes

= 15 / 36

= 5 / 12

Answer 2

The logic is there are six sides to each die, so for each number on one die you can pair with six different numbers on the other die. Therefore, the probability of rolling a prime number on two dice is 15/36, which reduces to 5/12