Two fair dice are rolled. Let `P(A_(i))gt0` donete the event that the sum of the faces of the dice is divisible by i.
Which one of the following events is most probable?
A. `A_(3)`
B. `A_(4)`
C. `A_(5)`
D. `A_(6)`
Correct Answer - D
Note that `A_(1)` is independent with all events `A_(1),A_(2),A_(3),A_(4)....,A_(12),` Now, total number of ordered pairs is 23.
`underset(22)( underbrace((1.1),(1,2),(1.3),...,(1,11)))+(1,12)`
Also that `A_(2),A_(3),andA_(3),A_(2)` are independent. Hence, there are...
Correct Answer - 2
Here `P(E)=1/2and P(F_(k))=""^(n)C_(k).(1)/(2^(n))`
Also, `P(EnnF_(k))=p` (exactly k heads are obtained and head obtained in first filp)
`=1/2""^(n-1)C_(k-1)((1)/(2))^(n-1)`
Events E and `f_(k)` are independent. Therefore,
`P(EnnF_(k))=P(E).P(F_(k))`
`or ""^(n-1)C_(k-1)xx(1)/(2^(n))=1/2xx""^(n)C_(k)(1)/(2^(n))`...
Correct Answer - C
`E_(1):{(4,1),...,(4,6)}to6"cases"`
`E_(2):{(1,2),...,(6,2)}to6"cases"`
`E_(3):"18 cases (sum of both is odd")`
`thereforeP(E_(1))=3/6=1/6=P(E_(2))`
`P(E_(3))=18/36=1/2`
`P(E_(1)nnE_(2))=1/36`
`P(E_(2)nnE_(3))=3/36=1/12`
Similarly `P(E_(3)nnE_(1))=1/12`
`P(E_(1)nnE_(2)nnE_(3))=0`
`therefore E_(1),E_(2),E_(3)` are not independent.