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Saturday, 31 October

JEE Main 2021 · MathsMultiple choiceSingle correctMediumCalculation

JEE Main 25 February 2021, Shift 2, Maths Q75

Question 75 of 90 in this shift, Maths question 15 of 30, Section A.

In a group of 400 people, 160 are smokers and non-vegetarian; 100 are smokers and vegetarian and the remaining 140 are non-smokers and vegetarian. Their chances of getting a particular chest disorder are 35%, 20% and 10% respectively. A person is chosen from the group at random and is found to be suffering from the chest disorder. The probability that the selected person is a smoker and non-vegetarian is :
  1. (1)745\frac{7}{45}
  2. (2)845\frac{8}{45}
  3. (3)2845\frac{28}{45}Official answer
  4. (4)1445\frac{14}{45}

Official answer

Option 3

NTA final key.

Chapter
Probability
Topic
Bayes' Theorem
Idea tested
Bayes' Theorem Application

Same idea in other shifts

Asked 9× in all
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Question text from the official JEE Main paper published by NTA; answer from the final answer key. Chapter, topic and idea tags, difficulty and skill are Lumi’s. Lumi analyses 108 of the 174 JEE Main shifts held from 2017 to 2026.