In a hostel, 60% of the students read Hindi newspaper, 40% read English newspaper and 20% read both Hindi and English newspapers. A student is selected at random.
(i) Find the probability that he reads neither Hindi nor English news paper.
(ii) If he reads Hindi newspaper, what is the probability that he reads English newspaper?
(iii) If he reads English newspaper, what is the probability that he reads Hindi newspaper?
Let P(A) be the probability of students reading Hindi newspaper.
∴P(A)=0.60
Let P(B) be the probability of them reading English newspaper.
∴P(B)=0.40
Let P(A∩B) be the probability them reading both.
Let 
be the probability them reading either one of them.
∴P(A∪B)
=P(A)+P(B)-P(A∩B)
=0.60+0.40-0.20
=0.80
(i)The probability that none of them reads either of them
= 1 – 0.8
= 0.2
=1/5
Tip – By conditional probability, 
where 
is the probability of occurrence of the event A given that B has already occurred.
(ii)The probability that he reads the English one given that he reads the Hindi one:
(iii)The probability that he reads the Hindi one given that he reads the English one:
