Correct Answer - `1//7`
Let E be the event which all three coins show tail and F be the event in which a coin shown tail. Therefor, `F={HHT}.` Hence, the required probability is
`thereforeP(E//F)=(P(EnnF))/(P(E))=(1)/(7)`
We know that, probability distribution P(X=r)=`""^(n)C_(r)(p)^( r)q^(n-r)`
Here, n=8,r=3,p=`1/2` and q=`1/2`
`therefore` Required probability=`""^(8)C_(3)(1/2)^(8-3)=(8!)/(5!3!)(1/2)^(8)`
`=(8cdot7cdot6)/(3cdot2)cdot1/(16cdot16)=7/32`
According to the equation, sample space
`S = {(H,H),(H,T),(T,1),(T,2),(T,3),(T,4),(T,5),(T,6)}`
In the above set, there are 8 elementary events, but all are not equally likely.
However, events (H,H) and (H,T) are...
Correct Answer - `(10)/(91)`
The required probability is
`(.^(3)C_(3) + .^(7)C_(3) + .^(4)C_(3))/(.^(14)C_(3)) = (1 + 35 + 4)/(14 xx 13 xx 2) = (40)/(14 xx 26) = (10)/(91)`
Since the trials are independent, so the probability that head appears on the fifth toss does not depend upon previous results of the tosses. Hence, required probability is equal to...
Let `E_(1)` be the event that the coin drawn is fair and `E_(2)` e the event that the coin drawn is biased. Therefore,
`P(E_(1))=m/NandP(E_(2))=(N-m)/(N)`
A is the event that on...
Correct Answer - A::D
Let `P(E)=eand P(F)=f`
`P(EuuF)-P(EnnF)=11/25`
`impliese+f-2ef=11/25" "(1)`
`P(barEnnbarF)=2/25`
`implies(1-e)(1-f)=2/25" "(2)`
From (1) and (2),
`ef=12/25and e+f=7/5`
Solving, we get
`e=4/5,f=3/5or e=3/5,f=4/5`
Correct Answer - D
`(d)` `P(T)=p`, `P(H)=1-p`
`:.` Required probability
`=P(T or HHT or HHHHT or ….)`
`=p+(1-p)^(2)p+(1-p)^(4)+….`
`=(p)/(1-(1-p)^(2))`
`=(p)/(2p-p^(2))=(2)/(3)`
`impliesp=(1)/(2)`