Question 10814 – APPSC-2016-DL-CS

We will use binomial distribution here.
Total possible outcomes will be 6*6=36
Lets first calculate probability of getting sum as 9. We will get sum as 9 when first dice and second dice will have number (3,6) ,(4,5) ,(5,4) ,(6,3). So total 4 possibility are there out of 36.
So Let probability of getting sum as 9 = P(A) = 4/36 = 1/9
Now
Probability of scoring 9 at least in one of the two times
= Probability of scoring 9 exactly one time + Probability of scoring 9 exactly two times