In a survey, it was found that 70% of people read Ittefaq, 60% read Sangbad, and 40% read both newspapers. If a person is chosen at random, find the probability that they read either Ittefaq or Sangbad.

Question: In a survey, it was found that 70% of people read Ittefaq, 60% read Sangbad, and 40% read both newspapers. If a person is chosen at random, find the probability that they read either Ittefaq or Sangbad.

Solution:
ধরি, ইত্তেফাক পড়ার ঘটনা A
এবং সংবাদ পড়ার ঘটনা B
P(A) = 70/100 = 7/10
P(B) = 60/100 = 6/10
P(A ∩ B)= 40/100 = 4/10

নিরপেক্ষভাবে বাছাই করলে একজন লোকের ইত্তেফাক বা সংবাদ পড়ার সম্ভাব্যতা P( A ∪ B)

∴ P(A ∪ B) = P(A) + P(B) - P(A ∩ B)
= (7/10) + (6/10) - (4/10)
= (7 + 6 - 4)/10
= 9/10