In a single throw of two dice, find the probability of

(i) getting a sum less than 6


(ii) getting a doublet of odd numbers


(iii) getting the sum as a prime number


(i) We know that,


Probability of occurrence of an event


Outcomes are (1, 1), (1, 2), (1, 3), (1, 4), (1, 5), (1, 6),


(2, 1), (2, 2), (2, 3), (2, 4), (2, 5), (2, 6),


(3, 1), (3, 2), (3, 3), (3, 4), (3, 5), (3, 6),


(4, 1), (4, 2), (4, 3), (4, 4), (4, 5), (4, 6) ,


(5, 1), (5, 2), (5, 3), (5, 4), (5, 5), (5, 6) ,


(6, 1), (6, 2), (6, 3), (6, 4), (6, 5), (6, 6)


Total no.of outcomes are 36


In that only (1, 1), (1, 2), (1, 3), (1, 4), (2, 1), (2, 2), (2, 3), (3, 1), (3, 2), (4, 1) are our desired outputs as there sum is less than 6


Therefore no.of desired outcomes are 10


Therefore, the probability of getting a sum less than 6



Conclusion: Probability of getting a sum less than 6, when two dice are rolled is


(ii) We know that,


Probability of occurrence of an event


In (a, b) if a=b then it is called a doublet


Total doublets are (1, 1), (2, 2), (3, 3), (4, 4), (5, 5), (6, 6)


In (a, b) if a=b and if a, b both are odd then it is called a doublet


Odd doublets are (1, 1), (3, 3), (5, 5)


Outcomes are (1, 1), (1, 2), (1, 3), (1, 4), (1, 5), (1, 6),


(2, 1), (2, 2), (2, 3), (2, 4), (2, 5), (2, 6),


(3, 1), (3, 2), (3, 3), (3, 4), (3, 5), (3, 6),


(4, 1), (4, 2), (4, 3), (4, 4), (4, 5), (4, 6) ,


(5, 1), (5, 2), (5, 3), (5, 4), (5, 5), (5, 6) ,


(6, 1), (6, 2), (6, 3), (6, 4), (6, 5), (6, 6)


Total no.of outcomes are 36 and desired outcomes are 3


Therefore, probability of getting doublet of odd numbers



Conclusion: Probability of getting doublet of odd numbers, when two dice are rolled is


(iii) We know that,


Probability of occurrence of an event


Outcomes are (1, 1), (1, 2), (1, 3), (1, 4), (1, 5), (1, 6),


(2, 1), (2, 2), (2, 3), (2, 4), (2, 5), (2, 6),


(3, 1), (3, 2), (3, 3), (3, 4), (3, 5), (3, 6),


(4, 1), (4, 2), (4, 3), (4, 4), (4, 5), (4, 6) ,


(5, 1), (5, 2), (5, 3), (5, 4), (5, 5), (5, 6) ,


(6, 1), (6, 2), (6, 3), (6, 4), (6, 5), (6, 6)


Total no.of outcomes are 36


Desired outputs are (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)


Total no.of desired outputs are 15


Therefore, probability of getting the sum as a prime number



Conclusion: Probability of getting the sum as a prime number, when two dice are rolled is


1