Question
Mathematics Question on Conditional Probability
In rolling two fair dice, what is the probability of obtaining a sum greater than 3 but not exceeding 6 ?
A
21
B
31
C
41
D
61
Answer
31
Explanation
Solution
Let S be the sample space
∴ n(S) 36
Events
[sum greater than 3 but not exceeding 6]
= {(2, 2), (3, 1), (1, 3), (4, 1), (1, 4), (5, 1) (1, 5),
(3, 2), (2, 3), (4, 2), (2,4), (3, 3)}
⇒ n(E) 12
∴ Required probability = n(S)n(E)=3612=31