Question

Two dice are rolled find the probability that the sum is atleast 9

Answer 1

Two dice are rolled,
» Possible 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)

The no.of possible outcomes = 36

The favourable outcomes are; (whose sum is atleast 9)
(3,6) (4,5) (4,6) (5,4) (5,5) (5,6) (6,3) (6,4) (6,5) (6,6)

The no,of favourable outcomes= 10

{Here, at least 9 means 9 or more then 9}

Probability = No.of favourable outcomes/no.of possible outcomes

= 10/36

= 5/18