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Saturday, 31 October

JEE Main 2021 · MathsMultiple choiceSingle correctMediumApplication

JEE Main 17 March 2021, Shift 2, Maths Q71

Question 71 of 90 in this shift, Maths question 11 of 30, Section A.

Let a computer program generate only the digits 0 and 1 to form a string of binary numbers with probability of occurrence of 0 at even places be 12\frac{1}{2} and probability of occurrence of 0 at the odd place be 13\frac{1}{3}. Then the probability that ‘10’ is followed by ‘01’ is equal to :
  1. (1)19\frac{1}{9}Official answer
  2. (2)16\frac{1}{6}
  3. (3)13\frac{1}{3}
  4. (4)118\frac{1}{18}

Official answer

Option 1

NTA final key.

Chapter
Probability
Topic
Conditional Probability
Idea tested
Multiplication Rule of Probability

Same idea in other shifts

Asked 2× in all
  1. 25 Feb 2021, Shift 1 · Q75When a missile is fired from a ship, the probability that it is intercepted is 13\frac{1}{3} and the probability that the missile hits the…EasySingle 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.