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Saturday, 31 October

JEE Main 2024 · MathsMultiple choiceSingle correctEasyCalculation

JEE Main 6 April 2024, Shift 1, Maths Q20

Question 20 of 90 in this shift, Maths question 20 of 30, Section A.

A company has two plants AA and BB to manufacture motorcycles. 60%60\% motorcycles are manufactured at plant AA and the remaining are manufactured at plant BB. 80%80\% of the motorcycles manufactured at plant AA are rated of the standard quality, while 90%90\% of the motorcycles manufactured at plant BB are rated of the standard quality. A motorcycle picked up randomly from the total production is found to be of the standard quality. If pp is the probability that it was manufactured at plant BB, then 126p126p is
  1. (1)5656
  2. (2)6464
  3. (3)6666
  4. (4)5454Official answer

Official answer

Option 4

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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  5. 30 Jan 2024, Shift 2 · Q20Bag A contains 3 white, 7 red balls and Bag B contains 3 white, 2 red balls. One bag is selected at random and a ball is drawn from it.…EasySingle correct
  6. 8 Apr 2023, Shift 1 · Q18In a bolt factory, machines AA, BB and CC manufacture respectively 20%, 30% and 50% of the total bolts. Of their output 3, 4 and 2…EasySingle correct
  7. 24 Jun 2022, Shift 1 · Q4Bag A contains 2 white, 1 black and 3 red balls and bag B contains 3 black, 2 red and n white balls. One bag is chosen at random and 2…MediumSingle correct
  8. 25 Feb 2021, Shift 2 · Q75In a group of 400 people, 160 are smokers and non-vegetarian; 100 are smokers and vegetarian and the remaining 140 are non-smokers and…MediumSingle correct

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.