Probability Question 296

Question: Rahul has to write a project, probability that he will get a project copy is ?P?, probability that he will get a blue pen is ?q? and probability that he will get a black pen is 1/2, if he can complete the project either with blue or with black pen or with both and probability that he completed the project is 1/2 then $ P(1+q) $ is

Options:

A) $ \frac{1}{2} $

B) 1

C) $ \frac{1}{4} $

D) 2

Show Answer

Answer:

Correct Answer: B

Solution:

Lets define the events as probability of getting project copy [a] = p

Probability of getting blue pen [b] = q 0

Probability of getting black pen [c] = 1/2 Then $ P(AC\overline{B})+p(AC\overline{B})+p(ABC)=\frac{1}{2} $

$ p.q.\frac{1}{2}+p.\frac{1}{2}(1-q)+p.q.\frac{1}{2}=\frac{1}{2} $

$ \therefore pq+p-pq+pq=1 $

$ \therefore p(1+q)=1 $