Four persons independently solve a certain problem correctly with proabilities `1/2,3/4,1/4,1/8.` Then the probability that the problem is solved correctly by at least one of them is
A. `235/256`
B. `21/256`
C. `3/256`
D. `253/256`
Correct Answer - `(.^(7)P_(5))/(7^(5))`
In an 8-floor house, there are 7 floors above the ground floor.
Each person can leave the cabin at any of the seven floors, i.e., each person...
Correct Answer - C
The probabilities of solving the question by these three students are `1//3,2//7and 3//8,` respectively. Therefore,
`P(A)=(1)/(3),P(B)=2/7,P(C)=3/8`
Then probability of question solved by only one student is `P((A...
Correct Answer - C
Possiblities of getting 9 are `(5,4),(4,5),(6,43),(3,6).`
`thereforep=(4)/(36)=1/9andq=1-1/9=8/9`
Therefore, the required probability is
`""^(3)C_(2)q^(1)p^(2)=(3)((8)/(9))((1)/(9))^(2)=(8)/(143)`
Correct Answer - B::D
`P(X_(1))=1/2,P(X_(2))=1/4,P(X_(3))=1/4`
`P(X)=P(X_(1)nnX_(2)nnX_(3))+P(X_(1)nnX_(2)^(C)nnX_(3))`
`+P(X_(1)^(C)nnX_(2)nnX_(3))+P(X_(1)nnX_(2)nnX_(3)^(C))=1/4`
(1) `P(X_(1)^(C)//X)=(P(XnnX_(1)^(C)))/(P(X))=(1//32)/(1//4)=1/8`
(2) P [exactly two engines of the shp are functioning
`|X]=(7//32)/(1//4)=7/8`
(3) `P((X)/(X_(2)))=(P(XnnX_(2)))/(P(X_(2)))=(5//32)/(1//4)=5/8`
(4) `P((X)/(X_(1)))=(P(XnnX_(1)))/(P(X_(1)))=(7//32)/(1//2)=7/16`
Correct Answer - B
`(b)` Total no of outcomes `=6^(6)`
Number of ways of choosing `4` other different numbers is `"^(6)C_(2)` and choosing `2` out of remaining `4` can be lone...
Correct Answer - A
`(a)` Let us first distribute `4` left gloves to four person in `4!` ways.
If no one gets the corresponding right glove then no. of ways `=4!(1-(1)/(1!)+(1)/(2!)-(1)/(3!)+(1)/(4!))=9`...