Learn

Saturday, 31 October

JEE Main 2020 · MathsMultiple choiceSingle correctMediumMulti-step

JEE Main 4 September 2020, Shift 2, Maths Q68

Question 68 of 75 in this shift, Maths question 18 of 25.

In a game two players A and B take turns in throwing a pair of fair dice starting with player A and total of scores on the two dice, in each throw is noted. A wins the game if he throws a total of 6 before B throws a total of 7 and B wins the game if he throws a total of 7 before A throws a total of six. The game stops as soon as either of the players wins. The probability of A winning the game is :
  1. (1)56\frac{5}{6}
  2. (2)531\frac{5}{31}
  3. (3)3161\frac{31}{61}
  4. (4)3061\frac{30}{61}Official answer

Official answer

Option 4

NTA final key (Sep 2020).

Chapter
Probability
Topic
Conditional Probability
Idea tested
Conditional Probability in Infinite Games

Same topic in other shifts

All Conditional Probability questions
  1. 5 Apr 2026, Shift 1 · Q7A letter is known to have arrived by post either from KANPUR or from ANANTPUR. On the envelope just two consecutive letters AN are…MediumSingle correct
  2. 5 Apr 2026, Shift 2 · Q8The probabilities that players A and B of a team are selected for the captaincy for a tournament are 0.6 and 0.4, respectively. If A is…EasySingle correct
  3. 6 Apr 2026, Shift 2 · Q9A bag contains 6 blue and 6 green balls. Pairs of balls are drawn without replacement until the bag is empty. The probability that each…MediumSingle correct
  4. 8 Apr 2025, Shift 2 · Q9If AA and BB are two events such that P(A)=0.7P(A) = 0.7, P(B)=0.4P(B) = 0.4 and P(A∩B‾)=0.5P(A \cap \overline{B}) = 0.5, where B‾\overline{B} denotes the…MediumSingle correct
  5. 27 Jan 2024, Shift 1 · Q29A fair die is tossed repeatedly until a six is obtained. Let X denote the number of tosses required and let a=P(X=3)a=P(X=3), b=P(X≥3)b=P(X\geq3) and…MediumNumerical value
  6. 29 Jan 2024, Shift 1 · Q19A fair die is thrown until 2 appears. Then the probability, that 2 appears in even number of throws, isMediumSingle 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.